#18 Add sql index for unpublished exercises

And remove spec for remove feature

db/migrate/20201208095929_add_index_to_rfc.rb

@@ -0,0 +1,6 @@
+class AddIndexToRfc < ActiveRecord::Migration[5.2]
+  def change
+    add_index(:request_for_comments, %i[user_id user_type created_at],
+              order: { user_id: :asc, user_type: :asc, created_at: :desc }, name: :index_rfc_on_user_and_created_at)
+  end
+end

db/migrate/20201208132844_add_index_to_unpublished_exercises.rb

@@ -0,0 +1,5 @@
+class AddIndexToUnpublishedExercises < ActiveRecord::Migration[5.2]
+  def change
+    add_index(:exercises, :id, where: 'NOT unpublished', name: :index_unpublished_exercises)
+  end
+end

db/migrate/20201210113500_add_index_to_exercise_title.rb

@@ -0,0 +1,6 @@
+class AddIndexToExerciseTitle < ActiveRecord::Migration[5.2]
+  def change
+    enable_extension 'pg_trgm'
+    add_index :exercises, :title, using: :gin, opclass: :gin_trgm_ops
+  end
+end

db/schema.rb

@@ -10,9 +10,10 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_10_26_184633) do
+ActiveRecord::Schema.define(version: 2020_12_10_113500) do
 
   # These are extensions that must be enabled in order to support this database
+  enable_extension "pg_trgm"
   enable_extension "plpgsql"
 
   create_table "anomaly_notifications", id: :serial, force: :cascade do |t|
@@ -168,6 +169,8 @@ ActiveRecord::Schema.define(version: 2020_10_26_184633) do
     t.datetime "submission_deadline"
     t.datetime "late_submission_deadline"
     t.index ["id"], name: "index_exercises_on_id"
+    t.index ["id"], name: "index_unpublished_exercises", where: "(NOT unpublished)"
+    t.index ["title"], name: "index_exercises_on_title", opclass: :gin_trgm_ops, using: :gin
   end
 
   create_table "exercises_proxy_exercises", id: false, force: :cascade do |t|
@@ -331,6 +334,7 @@ ActiveRecord::Schema.define(version: 2020_10_26_184633) do
     t.integer "times_featured", default: 0
     t.index ["exercise_id"], name: "index_request_for_comments_on_exercise_id"
     t.index ["submission_id"], name: "index_request_for_comments_on_submission_id"
+    t.index ["user_id", "user_type", "created_at"], name: "index_rfc_on_user_and_created_at", order: { created_at: :desc }
   end
 
   create_table "searches", id: :serial, force: :cascade do |t|