Add cache_index migration

db/migrate/20171222183504_add_cache_index_to_project.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddCacheIndexToProject < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_column_with_default(:projects, :cache_index, :integer, default: 0)
+  end
+
+  def down
+    remove_column(:projects, :cache_index)
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20171220191323) do
+ActiveRecord::Schema.define(version: 20171222183504) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -1447,6 +1447,7 @@ ActiveRecord::Schema.define(version: 20171220191323) do
     t.boolean "repository_read_only"
     t.boolean "merge_requests_ff_only_enabled", default: false
     t.boolean "merge_requests_rebase_enabled", default: false, null: false
+    t.integer "cache_index", default: 0, null: false
   end
 
   add_index "projects", ["ci_id"], name: "index_projects_on_ci_id", using: :btree