Migrate database and models for study-group-based authorization

db/migrate/20220906142550_migrate_permissions_to_study_group.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class MigratePermissionsToStudyGroup < ActiveRecord::Migration[6.1]
+  # rubocop:disable Rails/SkipsModelValidations
+  def up
+    create_default_groups
+    migrate_internal_users
+    migrate_external_users
+  end
+
+  def create_default_groups
+    Consumer.find_each do |consumer|
+      StudyGroup.find_or_create_by!(consumer: consumer, external_id: nil) do |new_group|
+        new_group.name = "Default Study Group for #{consumer.name}"
+      end
+    end
+  end
+
+  def migrate_internal_users
+    # Internal users don't necessarily have a study group yet, which is needed for the teacher role
+    InternalUser.find_each do |user|
+      user.update_columns(platform_admin: true) if user.role == 'admin'
+
+      study_group = StudyGroup.find_by!(consumer: user.consumer, external_id: nil)
+
+      # All platform admins will "just" be a teacher in the study group
+      new_role = %w[admin teacher].include?(user.role) ? :teacher : :learner
+      membership = StudyGroupMembership.find_or_create_by!(study_group: study_group, user: user)
+      membership.update_columns(role: new_role)
+    end
+  end
+
+  def migrate_external_users
+    # All external users are (or will be) in a study group once launched through LTI
+    # and therefore don't need a new StudyGroupMembership
+    ExternalUser.where(role: 'admin').update(platform_admin: true)
+  end
+  # rubocop:enable Rails/SkipsModelValidations
+end