Use change instead of up/down in simple migrations

db/migrate/20180219153455_add_maximum_job_timeout_to_ci_runners.rb

@@ -3,11 +3,7 @@ class AddMaximumJobTimeoutToCiRunners < ActiveRecord::Migration
 
   DOWNTIME = false
 
-  def up
+  def change
     add_column :ci_runners, :maximum_job_timeout, :integer
   end
-
-  def down
-    remove_column :ci_runners, :maximum_job_timeout
-  end
 end

db/migrate/20180221022556_add_used_timeout_and_timeout_source_columns_to_ci_builds.rb

@@ -3,13 +3,8 @@ class AddUsedTimeoutAndTimeoutSourceColumnsToCiBuilds < ActiveRecord::Migration
 
   DOWNTIME = false
 
-  def up
+  def change
     add_column :ci_builds, :used_timeout, :integer
     add_column :ci_builds, :timeout_source, :string
   end
-
-  def down
-    remove_column :ci_builds, :used_timeout
-    remove_column :ci_builds, :timeout_source
-  end
 end