Prevent schema.rb reverting from datetime_with_timezone to datetime

config/initializers/active_record_data_types.rb

@@ -79,3 +79,8 @@ elsif Gitlab::Database.mysql?
     NATIVE_DATABASE_TYPES[:datetime_with_timezone] = { name: 'timestamp' }
   end
 end
+
+# Ensure `datetime_with_timezone` columns are correctly written to schema.rb
+if (ActiveRecord::Base.connection.active? rescue false)
+  ActiveRecord::Base.connection.send :reload_type_map
+end

db/migrate/20171019141859_fix_dev_timezone_schema.rb

@@ -0,0 +1,25 @@
+class FixDevTimezoneSchema < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # The this migrations tries to help solve unwanted changes to `schema.rb`
+  # while developing GitLab. Installations created before we started using
+  # `datetime_with_timezone` are likely to face this problem. Updating those
+  # columns to the new type should help fix this.
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  TIMEZONE_TABLES = %i(appearances ci_group_variables ci_pipeline_schedule_variables events gpg_keys gpg_signatures project_auto_devops)
+
+  def up
+    return unless Rails.env.development? || Rails.env.test?
+
+    TIMEZONE_TABLES.each do |table|
+      change_column table, :created_at, :datetime_with_timezone
+      change_column table, :updated_at, :datetime_with_timezone
+    end
+  end
+
+  def down
+  end
+end

db/schema.rb

@@ -649,8 +649,8 @@ ActiveRecord::Schema.define(version: 20171124150326) do
     t.datetime "created_at"
     t.datetime "updated_at"
     t.string "confirmation_token"
-    t.datetime "confirmed_at"
-    t.datetime "confirmation_sent_at"
+    t.datetime_with_timezone "confirmed_at"
+    t.datetime_with_timezone "confirmation_sent_at"
   end
 
   add_index "emails", ["confirmation_token"], name: "index_emails_on_confirmation_token", unique: true, using: :btree
@@ -1762,8 +1762,8 @@ ActiveRecord::Schema.define(version: 20171124150326) do
   add_index "user_agent_details", ["subject_id", "subject_type"], name: "index_user_agent_details_on_subject_id_and_subject_type", using: :btree
 
   create_table "user_custom_attributes", force: :cascade do |t|
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
+    t.datetime_with_timezone "created_at", null: false
+    t.datetime_with_timezone "updated_at", null: false
     t.integer "user_id", null: false
     t.string "key", null: false
     t.string "value", null: false