rake db:migrateでdevelopmentだけでなくtestもまとめてマイグレーション走らせるやつ for Rails 5.1

patch_migrate.ruby

module ActiveRecord::Tasks::DatabaseTasks
  class <<self
    prepend Module.new {
      def migrate(environment = env)
        each_current_configuration(environment) { |configuration|
          begin
            ActiveRecord::Base.establish_connection(configuration)
            super()
          ensure
            ActiveRecord::Base.establish_connection(environment.to_sym)
          end
        }
      end
    }
  end
end