Make the downtime_check task happy

Signed-off-by: Rémy Coutable <remy@rymai.me>

db/migrate/20130319214458_create_forked_project_links.rb

 # rubocop:disable all
 class CreateForkedProjectLinks < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :forked_project_links do |t|
       t.integer :forked_to_project_id, null: false

db/migrate/20130506090604_create_deploy_keys_projects.rb

 # rubocop:disable all
 class CreateDeployKeysProjects < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :deploy_keys_projects do |t|
       t.integer :deploy_key_id, null: false

db/migrate/20130617095603_create_users_groups.rb

 # rubocop:disable all
 class CreateUsersGroups < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :users_groups do |t|
       t.integer :group_access, null: false

db/migrate/20130711063759_create_project_group_links.rb

 # rubocop:disable all
 class CreateProjectGroupLinks < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :project_group_links do |t|
       t.integer :project_id, null: false

db/migrate/20131112114325_create_broadcast_messages.rb

 # rubocop:disable all
 class CreateBroadcastMessages < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :broadcast_messages do |t|
       t.text :message, null: false

db/migrate/20140122112253_create_merge_request_diffs.rb

 # rubocop:disable all
 class CreateMergeRequestDiffs < ActiveRecord::Migration
+  DOWNTIME = false
+
   def up
     create_table :merge_request_diffs do |t|
       t.string :state, null: false, default: 'collected'

db/migrate/20140209025651_create_emails.rb

 # rubocop:disable all
 class CreateEmails < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :emails do |t|
       t.integer  :user_id, null: false

db/migrate/20140625115202_create_users_star_projects.rb

 # rubocop:disable all
 class CreateUsersStarProjects < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :users_star_projects do |t|
       t.integer :project_id, null: false

db/migrate/20140729134820_create_labels.rb

 # rubocop:disable all
 class CreateLabels < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :labels do |t|
       t.string :title

db/migrate/20140729140420_create_label_links.rb

 # rubocop:disable all
 class CreateLabelLinks < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :label_links do |t|
       t.integer :label_id

db/migrate/20140914113604_add_members_table.rb

 # rubocop:disable all
 class AddMembersTable < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :members do |t|
       t.integer :access_level, null: false

db/migrate/20140914173417_remove_old_member_tables.rb

 # rubocop:disable all
 class RemoveOldMemberTables < ActiveRecord::Migration
+  DOWNTIME = false
+
   def up
     drop_table :users_groups
     drop_table :users_projects

db/migrate/20141118150935_add_audit_event.rb

 # rubocop:disable all
 class AddAuditEvent < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :audit_events do |t|
       t.integer :author_id, null: false

db/migrate/20141216155758_create_doorkeeper_tables.rb

 # rubocop:disable all
 class CreateDoorkeeperTables < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :oauth_applications do |t|
       t.string  :name,         null: false

db/migrate/20150108073740_create_application_settings.rb

 # rubocop:disable all
 class CreateApplicationSettings < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :application_settings do |t|
       t.integer :default_projects_limit

db/migrate/20150313012111_create_subscriptions_table.rb

 # rubocop:disable all
 class CreateSubscriptionsTable < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :subscriptions do |t|
       t.integer :user_id

db/migrate/20150806104937_create_abuse_reports.rb

 # rubocop:disable all
 class CreateAbuseReports < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :abuse_reports do |t|
       t.integer :reporter_id

db/migrate/20151103134857_create_lfs_objects.rb

 # rubocop:disable all
 class CreateLfsObjects < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :lfs_objects do |t|
       t.string :oid, null: false, unique: true

db/migrate/20151103134958_create_lfs_objects_projects.rb

 # rubocop:disable all
 class CreateLfsObjectsProjects < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :lfs_objects_projects do |t|
       t.integer :lfs_object_id, null: false

db/migrate/20151105094515_create_releases.rb

 # rubocop:disable all
 class CreateReleases < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :releases do |t|
       t.string :tag

db/migrate/20160212123307_create_tasks.rb

 # rubocop:disable all
 class CreateTasks < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :tasks do |t|
       t.references :user, null: false, index: true

db/migrate/20160416180807_add_award_emoji.rb

 # rubocop:disable all
 class AddAwardEmoji < ActiveRecord::Migration
+  DOWNTIME = false
+
   def change
     create_table :award_emoji do |t|
       t.string :name