Remove self monitoring project migration

db/post_migrate/20190801072937_add_gitlab_instance_administration_project.rb

-# frozen_string_literal: true
-
-class AddGitlabInstanceAdministrationProject < ActiveRecord::Migration[5.2]
-  DOWNTIME = false
-
-  disable_ddl_transaction!
-
-  def up
-    BackgroundMigrationWorker.perform_async('AddGitlabInstanceAdministrationProject', [])
-  end
-
-  def down
-    ApplicationSetting.current_without_cache
-      &.instance_administration_project
-      &.owner
-      &.destroy!
-  end
-end

spec/migrations/add_gitlab_instance_administration_project_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-require Rails.root.join('db', 'post_migrate', '20190801072937_add_gitlab_instance_administration_project.rb')
-
-describe AddGitlabInstanceAdministrationProject, :migration do
-  let(:application_settings) { table(:application_settings) }
-  let(:users)                { table(:users) }
-
-  let(:prometheus_settings) do
-    {
-      enable: true,
-      listen_address: 'localhost:9090'
-    }
-  end
-
-  before do
-    stub_env('IN_MEMORY_APPLICATION_SETTINGS', 'false')
-
-    stub_config(prometheus: prometheus_settings)
-  end
-
-  describe 'down' do
-    let!(:application_setting) { application_settings.create! }
-    let!(:user) { users.create!(admin: true, email: 'admin1@example.com', projects_limit: 10, state: :active) }
-
-    it 'deletes group and project' do
-      migrate!
-
-      expect(Project.count).to eq(1)
-      expect(Group.count).to eq(1)
-
-      schema_migrate_down!
-
-      expect(Project.count).to eq(0)
-      expect(Group.count).to eq(0)
-    end
-  end
-end