Remove default value from cache_index migration

db/migrate/20171222183504_add_cache_index_to_project.rb

@@ -7,13 +7,7 @@ class AddCacheIndexToProject < ActiveRecord::Migration
   # 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)
+  def change
+    add_column :projects, :cache_index, :integer
   end
 end

db/schema.rb

@@ -1447,7 +1447,7 @@ ActiveRecord::Schema.define(version: 20171222183504) 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
+    t.integer "cache_index"
   end
 
   add_index "projects", ["ci_id"], name: "index_projects_on_ci_id", using: :btree