diff --git a/db/schema.rb b/db/schema.rb
index aab3e92b..f84e45d1 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -1,4 +1,3 @@
-# encoding: UTF-8
 # This file is auto-generated from the current state of the database. Instead
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
@@ -11,417 +10,402 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180904115948) do
+ActiveRecord::Schema.define(version: 2018_09_04_115948) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
   create_table "anomaly_notifications", force: :cascade do |t|
-    t.integer  "user_id"
-    t.string   "user_type"
-    t.integer  "exercise_id"
-    t.integer  "exercise_collection_id"
-    t.string   "reason"
+    t.integer "user_id"
+    t.string "user_type"
+    t.integer "exercise_id"
+    t.integer "exercise_collection_id"
+    t.string "reason"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["exercise_collection_id"], name: "index_anomaly_notifications_on_exercise_collection_id"
+    t.index ["exercise_id"], name: "index_anomaly_notifications_on_exercise_id"
+    t.index ["user_type", "user_id"], name: "index_anomaly_notifications_on_user_type_and_user_id"
   end
 
-  add_index "anomaly_notifications", ["exercise_collection_id"], name: "index_anomaly_notifications_on_exercise_collection_id", using: :btree
-  add_index "anomaly_notifications", ["exercise_id"], name: "index_anomaly_notifications_on_exercise_id", using: :btree
-  add_index "anomaly_notifications", ["user_type", "user_id"], name: "index_anomaly_notifications_on_user_type_and_user_id", using: :btree
-
   create_table "code_harbor_links", force: :cascade do |t|
-    t.string   "oauth2token", limit: 255
+    t.string "oauth2token", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "user_id"
+    t.integer "user_id"
+    t.index ["user_id"], name: "index_code_harbor_links_on_user_id"
   end
 
-  add_index "code_harbor_links", ["user_id"], name: "index_code_harbor_links_on_user_id", using: :btree
-
   create_table "comments", force: :cascade do |t|
-    t.integer  "user_id"
-    t.integer  "file_id"
-    t.string   "user_type",  limit: 255
-    t.integer  "row"
-    t.integer  "column"
-    t.text     "text"
+    t.integer "user_id"
+    t.integer "file_id"
+    t.string "user_type", limit: 255
+    t.integer "row"
+    t.integer "column"
+    t.text "text"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["file_id"], name: "index_comments_on_file_id"
+    t.index ["user_id"], name: "index_comments_on_user_id"
   end
 
-  add_index "comments", ["file_id"], name: "index_comments_on_file_id", using: :btree
-  add_index "comments", ["user_id"], name: "index_comments_on_user_id", using: :btree
-
   create_table "consumers", force: :cascade do |t|
-    t.string   "name",         limit: 255
+    t.string "name", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "oauth_key",    limit: 255
-    t.string   "oauth_secret", limit: 255
+    t.string "oauth_key", limit: 255
+    t.string "oauth_secret", limit: 255
   end
 
   create_table "error_template_attributes", force: :cascade do |t|
-    t.string   "key"
-    t.string   "regex"
-    t.datetime "created_at",  null: false
-    t.datetime "updated_at",  null: false
-    t.text     "description"
-    t.boolean  "important"
+    t.string "key"
+    t.string "regex"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.text "description"
+    t.boolean "important"
   end
 
   create_table "error_template_attributes_templates", id: false, force: :cascade do |t|
-    t.integer "error_template_id",           null: false
+    t.integer "error_template_id", null: false
     t.integer "error_template_attribute_id", null: false
   end
 
   create_table "error_templates", force: :cascade do |t|
-    t.integer  "execution_environment_id"
-    t.string   "name"
-    t.string   "signature"
-    t.datetime "created_at",               null: false
-    t.datetime "updated_at",               null: false
-    t.text     "description"
-    t.text     "hint"
+    t.integer "execution_environment_id"
+    t.string "name"
+    t.string "signature"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.text "description"
+    t.text "hint"
   end
 
   create_table "errors", force: :cascade do |t|
-    t.integer  "execution_environment_id"
-    t.text     "message"
+    t.integer "execution_environment_id"
+    t.text "message"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "submission_id"
+    t.integer "submission_id"
+    t.index ["submission_id"], name: "index_errors_on_submission_id"
   end
 
-  add_index "errors", ["submission_id"], name: "index_errors_on_submission_id", using: :btree
-
   create_table "events", force: :cascade do |t|
-    t.string   "category"
-    t.string   "data"
-    t.integer  "user_id"
-    t.string   "user_type"
-    t.integer  "exercise_id"
-    t.integer  "file_id"
-    t.datetime "created_at",  null: false
-    t.datetime "updated_at",  null: false
+    t.string "category"
+    t.string "data"
+    t.integer "user_id"
+    t.string "user_type"
+    t.integer "exercise_id"
+    t.integer "file_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
   create_table "execution_environments", force: :cascade do |t|
-    t.string   "docker_image",             limit: 255
-    t.string   "name",                     limit: 255
+    t.string "docker_image", limit: 255
+    t.string "name", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "run_command",              limit: 255
-    t.string   "test_command",             limit: 255
-    t.string   "testing_framework",        limit: 255
-    t.text     "help"
-    t.string   "exposed_ports",            limit: 255
-    t.integer  "permitted_execution_time"
-    t.integer  "user_id"
-    t.string   "user_type",                limit: 255
-    t.integer  "pool_size"
-    t.integer  "file_type_id"
-    t.integer  "memory_limit"
-    t.boolean  "network_enabled"
+    t.string "run_command", limit: 255
+    t.string "test_command", limit: 255
+    t.string "testing_framework", limit: 255
+    t.text "help"
+    t.string "exposed_ports", limit: 255
+    t.integer "permitted_execution_time"
+    t.integer "user_id"
+    t.string "user_type", limit: 255
+    t.integer "pool_size"
+    t.integer "file_type_id"
+    t.integer "memory_limit"
+    t.boolean "network_enabled"
   end
 
   create_table "exercise_collection_items", force: :cascade do |t|
     t.integer "exercise_collection_id"
     t.integer "exercise_id"
-    t.integer "position",               default: 0, null: false
+    t.integer "position", default: 0, null: false
+    t.index ["exercise_collection_id"], name: "index_exercise_collection_items_on_exercise_collection_id"
+    t.index ["exercise_id"], name: "index_exercise_collection_items_on_exercise_id"
   end
 
-  add_index "exercise_collection_items", ["exercise_collection_id"], name: "index_exercise_collection_items_on_exercise_collection_id", using: :btree
-  add_index "exercise_collection_items", ["exercise_id"], name: "index_exercise_collection_items_on_exercise_id", using: :btree
-
   create_table "exercise_collections", force: :cascade do |t|
-    t.string   "name"
+    t.string "name"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.boolean  "use_anomaly_detection", default: false
-    t.integer  "user_id"
-    t.string   "user_type"
+    t.boolean "use_anomaly_detection", default: false
+    t.integer "user_id"
+    t.string "user_type"
+    t.index ["user_type", "user_id"], name: "index_exercise_collections_on_user_type_and_user_id"
   end
 
-  add_index "exercise_collections", ["user_type", "user_id"], name: "index_exercise_collections_on_user_type_and_user_id", using: :btree
-
   create_table "exercise_tags", force: :cascade do |t|
     t.integer "exercise_id"
     t.integer "tag_id"
-    t.integer "factor",      default: 1
+    t.integer "factor", default: 1
   end
 
   create_table "exercises", force: :cascade do |t|
-    t.text     "description"
-    t.integer  "execution_environment_id"
-    t.string   "title",                    limit: 255
+    t.text "description"
+    t.integer "execution_environment_id"
+    t.string "title", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "user_id"
-    t.text     "instructions"
-    t.boolean  "public"
-    t.string   "user_type",                limit: 255
-    t.string   "token",                    limit: 255
-    t.boolean  "hide_file_tree"
-    t.boolean  "allow_file_creation"
-    t.boolean  "allow_auto_completion",                default: false
-    t.integer  "expected_difficulty",                  default: 1
+    t.integer "user_id"
+    t.text "instructions"
+    t.boolean "public"
+    t.string "user_type", limit: 255
+    t.string "token", limit: 255
+    t.boolean "hide_file_tree"
+    t.boolean "allow_file_creation"
+    t.boolean "allow_auto_completion", default: false
+    t.integer "expected_difficulty", default: 1
+    t.index ["id"], name: "index_exercises_on_id"
   end
 
-  add_index "exercises", ["id"], name: "index_exercises_on_id", using: :btree
-
   create_table "exercises_proxy_exercises", id: false, force: :cascade do |t|
-    t.integer  "proxy_exercise_id"
-    t.integer  "exercise_id"
+    t.integer "proxy_exercise_id"
+    t.integer "exercise_id"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["exercise_id"], name: "index_exercises_proxy_exercises_on_exercise_id"
+    t.index ["proxy_exercise_id"], name: "index_exercises_proxy_exercises_on_proxy_exercise_id"
   end
 
-  add_index "exercises_proxy_exercises", ["exercise_id"], name: "index_exercises_proxy_exercises_on_exercise_id", using: :btree
-  add_index "exercises_proxy_exercises", ["proxy_exercise_id"], name: "index_exercises_proxy_exercises_on_proxy_exercise_id", using: :btree
-
   create_table "external_users", force: :cascade do |t|
-    t.integer  "consumer_id"
-    t.string   "email",       limit: 255
-    t.string   "external_id", limit: 255
-    t.string   "name",        limit: 255
+    t.integer "consumer_id"
+    t.string "email", limit: 255
+    t.string "external_id", limit: 255
+    t.string "name", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "file_templates", force: :cascade do |t|
-    t.string   "name",         limit: 255
-    t.text     "content"
-    t.integer  "file_type_id"
+    t.string "name", limit: 255
+    t.text "content"
+    t.integer "file_type_id"
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "file_types", force: :cascade do |t|
-    t.string   "editor_mode",    limit: 255
-    t.string   "file_extension", limit: 255
-    t.integer  "indent_size"
-    t.string   "name",           limit: 255
-    t.integer  "user_id"
+    t.string "editor_mode", limit: 255
+    t.string "file_extension", limit: 255
+    t.integer "indent_size"
+    t.string "name", limit: 255
+    t.integer "user_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.boolean  "executable"
-    t.boolean  "renderable"
-    t.string   "user_type",      limit: 255
-    t.boolean  "binary"
+    t.boolean "executable"
+    t.boolean "renderable"
+    t.string "user_type", limit: 255
+    t.boolean "binary"
   end
 
   create_table "files", force: :cascade do |t|
-    t.text     "content"
-    t.integer  "context_id"
-    t.string   "context_type",     limit: 255
-    t.integer  "file_id"
-    t.integer  "file_type_id"
-    t.boolean  "hidden"
-    t.string   "name",             limit: 255
-    t.boolean  "read_only"
+    t.text "content"
+    t.integer "context_id"
+    t.string "context_type", limit: 255
+    t.integer "file_id"
+    t.integer "file_type_id"
+    t.boolean "hidden"
+    t.string "name", limit: 255
+    t.boolean "read_only"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "native_file",      limit: 255
-    t.string   "role",             limit: 255
-    t.string   "hashed_content",   limit: 255
-    t.string   "feedback_message", limit: 255
-    t.float    "weight"
-    t.string   "path",             limit: 255
-    t.integer  "file_template_id"
+    t.string "native_file", limit: 255
+    t.string "role", limit: 255
+    t.string "hashed_content", limit: 255
+    t.string "feedback_message", limit: 255
+    t.float "weight"
+    t.string "path", limit: 255
+    t.integer "file_template_id"
+    t.index ["context_id", "context_type"], name: "index_files_on_context_id_and_context_type"
   end
 
-  add_index "files", ["context_id", "context_type"], name: "index_files_on_context_id_and_context_type", using: :btree
-
   create_table "hints", force: :cascade do |t|
-    t.integer  "execution_environment_id"
-    t.string   "locale",                   limit: 255
-    t.text     "message"
-    t.string   "name",                     limit: 255
-    t.string   "regular_expression",       limit: 255
+    t.integer "execution_environment_id"
+    t.string "locale", limit: 255
+    t.text "message"
+    t.string "name", limit: 255
+    t.string "regular_expression", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "internal_users", force: :cascade do |t|
-    t.integer  "consumer_id"
-    t.string   "email",                           limit: 255
-    t.string   "name",                            limit: 255
-    t.string   "role",                            limit: 255
+    t.integer "consumer_id"
+    t.string "email", limit: 255
+    t.string "name", limit: 255
+    t.string "role", limit: 255
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "crypted_password",                limit: 255
-    t.string   "salt",                            limit: 255
-    t.integer  "failed_logins_count",                         default: 0
+    t.string "crypted_password", limit: 255
+    t.string "salt", limit: 255
+    t.integer "failed_logins_count", default: 0
     t.datetime "lock_expires_at"
-    t.string   "unlock_token",                    limit: 255
-    t.string   "remember_me_token",               limit: 255
+    t.string "unlock_token", limit: 255
+    t.string "remember_me_token", limit: 255
     t.datetime "remember_me_token_expires_at"
-    t.string   "reset_password_token",            limit: 255
+    t.string "reset_password_token", limit: 255
     t.datetime "reset_password_token_expires_at"
     t.datetime "reset_password_email_sent_at"
-    t.string   "activation_state",                limit: 255
-    t.string   "activation_token",                limit: 255
+    t.string "activation_state", limit: 255
+    t.string "activation_token", limit: 255
     t.datetime "activation_token_expires_at"
+    t.index ["activation_token"], name: "index_internal_users_on_activation_token"
+    t.index ["email"], name: "index_internal_users_on_email", unique: true
+    t.index ["remember_me_token"], name: "index_internal_users_on_remember_me_token"
+    t.index ["reset_password_token"], name: "index_internal_users_on_reset_password_token"
   end
 
-  add_index "internal_users", ["activation_token"], name: "index_internal_users_on_activation_token", using: :btree
-  add_index "internal_users", ["email"], name: "index_internal_users_on_email", unique: true, using: :btree
-  add_index "internal_users", ["remember_me_token"], name: "index_internal_users_on_remember_me_token", using: :btree
-  add_index "internal_users", ["reset_password_token"], name: "index_internal_users_on_reset_password_token", using: :btree
-
   create_table "interventions", force: :cascade do |t|
-    t.string   "name"
-    t.text     "markup"
+    t.string "name"
+    t.text "markup"
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "lti_parameters", force: :cascade do |t|
-    t.integer  "external_users_id"
-    t.integer  "consumers_id"
-    t.integer  "exercises_id"
-    t.jsonb    "lti_parameters",    default: {}, null: false
+    t.integer "external_users_id"
+    t.integer "consumers_id"
+    t.integer "exercises_id"
+    t.jsonb "lti_parameters", default: {}, null: false
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["external_users_id"], name: "index_lti_parameters_on_external_users_id"
   end
 
-  add_index "lti_parameters", ["external_users_id"], name: "index_lti_parameters_on_external_users_id", using: :btree
-
   create_table "proxy_exercises", force: :cascade do |t|
-    t.string   "title"
-    t.string   "description"
-    t.string   "token"
+    t.string "title"
+    t.string "description"
+    t.string "token"
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "remote_evaluation_mappings", force: :cascade do |t|
-    t.integer  "user_id",          null: false
-    t.integer  "exercise_id",      null: false
-    t.string   "validation_token", null: false
+    t.integer "user_id", null: false
+    t.integer "exercise_id", null: false
+    t.string "validation_token", null: false
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "request_for_comments", force: :cascade do |t|
-    t.integer  "user_id",                                        null: false
-    t.integer  "exercise_id",                                    null: false
-    t.integer  "file_id",                                        null: false
+    t.integer "user_id", null: false
+    t.integer "exercise_id", null: false
+    t.integer "file_id", null: false
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "user_type",          limit: 255
-    t.text     "question"
-    t.boolean  "solved",                         default: false
-    t.integer  "submission_id"
-    t.text     "thank_you_note"
-    t.boolean  "full_score_reached",             default: false
-    t.integer  "times_featured",                 default: 0
+    t.string "user_type", limit: 255
+    t.text "question"
+    t.boolean "solved", default: false
+    t.integer "submission_id"
+    t.text "thank_you_note"
+    t.boolean "full_score_reached", default: false
+    t.integer "times_featured", default: 0
   end
 
   create_table "searches", force: :cascade do |t|
-    t.integer  "exercise_id", null: false
-    t.integer  "user_id",     null: false
-    t.string   "user_type",   null: false
-    t.string   "search"
+    t.integer "exercise_id", null: false
+    t.integer "user_id", null: false
+    t.string "user_type", null: false
+    t.string "search"
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "structured_error_attributes", force: :cascade do |t|
-    t.integer  "structured_error_id"
-    t.integer  "error_template_attribute_id"
-    t.string   "value"
-    t.datetime "created_at",                  null: false
-    t.datetime "updated_at",                  null: false
-    t.boolean  "match"
+    t.integer "structured_error_id"
+    t.integer "error_template_attribute_id"
+    t.string "value"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.boolean "match"
   end
 
   create_table "structured_errors", force: :cascade do |t|
-    t.integer  "error_template_id"
-    t.datetime "created_at",        null: false
-    t.datetime "updated_at",        null: false
-    t.integer  "submission_id"
+    t.integer "error_template_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.integer "submission_id"
+    t.index ["submission_id"], name: "index_structured_errors_on_submission_id"
   end
 
-  add_index "structured_errors", ["submission_id"], name: "index_structured_errors_on_submission_id", using: :btree
-
   create_table "submissions", force: :cascade do |t|
-    t.integer  "exercise_id"
-    t.float    "score"
-    t.integer  "user_id"
+    t.integer "exercise_id"
+    t.float "score"
+    t.integer "user_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "cause",       limit: 255
-    t.string   "user_type",   limit: 255
+    t.string "cause", limit: 255
+    t.string "user_type", limit: 255
+    t.index ["exercise_id"], name: "index_submissions_on_exercise_id"
+    t.index ["user_id"], name: "index_submissions_on_user_id"
   end
 
-  add_index "submissions", ["exercise_id"], name: "index_submissions_on_exercise_id", using: :btree
-  add_index "submissions", ["user_id"], name: "index_submissions_on_user_id", using: :btree
-
   create_table "subscriptions", force: :cascade do |t|
-    t.integer  "user_id"
-    t.string   "user_type"
-    t.integer  "request_for_comment_id"
-    t.string   "subscription_type"
-    t.datetime "created_at",             null: false
-    t.datetime "updated_at",             null: false
-    t.boolean  "deleted"
+    t.integer "user_id"
+    t.string "user_type"
+    t.integer "request_for_comment_id"
+    t.string "subscription_type"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.boolean "deleted"
   end
 
   create_table "tags", force: :cascade do |t|
-    t.string   "name",       null: false
+    t.string "name", null: false
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "testruns", force: :cascade do |t|
-    t.boolean  "passed"
-    t.text     "output"
-    t.integer  "file_id"
-    t.integer  "submission_id"
+    t.boolean "passed"
+    t.text "output"
+    t.integer "file_id"
+    t.integer "submission_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "cause"
+    t.string "cause"
+    t.index ["submission_id"], name: "index_testruns_on_submission_id"
   end
 
-  add_index "testruns", ["submission_id"], name: "index_testruns_on_submission_id", using: :btree
-
   create_table "user_exercise_feedbacks", force: :cascade do |t|
-    t.integer  "exercise_id",             null: false
-    t.integer  "user_id",                 null: false
-    t.string   "user_type",               null: false
-    t.integer  "difficulty"
-    t.integer  "working_time_seconds"
-    t.string   "feedback_text"
-    t.integer  "user_estimated_worktime"
-    t.datetime "created_at",              null: false
-    t.datetime "updated_at",              null: false
+    t.integer "exercise_id", null: false
+    t.integer "user_id", null: false
+    t.string "user_type", null: false
+    t.integer "difficulty"
+    t.integer "working_time_seconds"
+    t.string "feedback_text"
+    t.integer "user_estimated_worktime"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
   create_table "user_exercise_interventions", force: :cascade do |t|
-    t.integer  "user_id"
-    t.string   "user_type"
-    t.integer  "exercise_id"
-    t.integer  "intervention_id"
-    t.integer  "accumulated_worktime_s"
-    t.text     "reason"
+    t.integer "user_id"
+    t.string "user_type"
+    t.integer "exercise_id"
+    t.integer "intervention_id"
+    t.integer "accumulated_worktime_s"
+    t.text "reason"
     t.datetime "created_at"
     t.datetime "updated_at"
   end
 
   create_table "user_proxy_exercise_exercises", force: :cascade do |t|
-    t.integer  "user_id"
-    t.string   "user_type"
-    t.integer  "proxy_exercise_id"
-    t.integer  "exercise_id"
+    t.integer "user_id"
+    t.string "user_type"
+    t.integer "proxy_exercise_id"
+    t.integer "exercise_id"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "reason"
+    t.string "reason"
+    t.index ["exercise_id"], name: "index_user_proxy_exercise_exercises_on_exercise_id"
+    t.index ["proxy_exercise_id"], name: "index_user_proxy_exercise_exercises_on_proxy_exercise_id"
+    t.index ["user_type", "user_id"], name: "index_user_proxy_exercise_exercises_on_user_type_and_user_id"
   end
 
-  add_index "user_proxy_exercise_exercises", ["exercise_id"], name: "index_user_proxy_exercise_exercises_on_exercise_id", using: :btree
-  add_index "user_proxy_exercise_exercises", ["proxy_exercise_id"], name: "index_user_proxy_exercise_exercises_on_proxy_exercise_id", using: :btree
-  add_index "user_proxy_exercise_exercises", ["user_type", "user_id"], name: "index_user_proxy_exercise_exercises_on_user_type_and_user_id", using: :btree
-
 end
diff --git a/db/seeds/development.rb b/db/seeds/development.rb
index b0c550c0..0aedc789 100644
--- a/db/seeds/development.rb
+++ b/db/seeds/development.rb
@@ -3,6 +3,8 @@ FactoryBot.create(:consumer)
 FactoryBot.create(:consumer, name: 'openSAP')
 
 # users
+# Set default_url_options explicitly, required for rake task
+Rails.application.routes.default_url_options = Rails.application.config.action_mailer.default_url_options
 [:admin, :external_user, :teacher].each { |factory_name| FactoryBot.create(factory_name) }
 
 # execution environments