DEV: Move UserApiKey scopes to dedicated table (#10704)

This has no functional impact yet, but it is the first step in adding more granular scopes to UserApiKeys

db/migrate/20200918095554_add_user_api_key_scopes.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+class AddUserApiKeyScopes < ActiveRecord::Migration[6.0]
+  def change
+    create_table :user_api_key_scopes do |t|
+      t.integer :user_api_key_id, null: false
+      t.string :name, null: false
+      t.timestamps
+    end
+
+    add_index :user_api_key_scopes, :user_api_key_id
+
+    reversible do |dir|
+      dir.up do
+        execute <<~SQL
+          INSERT INTO user_api_key_scopes
+          (
+            user_api_key_id,
+            name,
+            created_at,
+            updated_at
+          )
+          SELECT
+            user_api_keys.id,
+            unnest(user_api_keys.scopes),
+            created_at,
+            updated_at
+          FROM user_api_keys
+        SQL
+
+        Migration::SafeMigrate.disable!
+        change_column_null :user_api_keys, :scopes, true
+        change_column_default :user_api_keys, :scopes, nil
+        Migration::SafeMigrate.enable!
+
+        Migration::ColumnDropper.mark_readonly(:user_api_keys, :scopes)
+      end
+
+      dir.down do
+        change_column_null :user_api_keys, :scopes, false
+        change_column_default :user_api_keys, :scopes, []
+        Migration::ColumnDropper.drop_readonly(:user_api_keys, :scopes)
+      end
+    end
+  end
+end