Use add_column_with_default in migration

db/migrate/20180601213245_add_deploy_strategy_to_project_auto_devops.rb

@@ -7,9 +7,13 @@ class AddDeployStrategyToProjectAutoDevops < ActiveRecord::Migration
   # Set this constant to true if this migration requires downtime.
   DOWNTIME = false
 
-  def change
-    change_table :project_auto_devops do |t|
-      t.integer :deploy_strategy, null: false, default: 0
+  disable_ddl_transaction!
+
+  def up
+    add_column_with_default :project_auto_devops, :deploy_strategy, :integer, default: 0, allow_null: false
   end
+
+  def down
+    remove_column :project_auto_devops, :deploy_strategy
   end
 end