Remove background migration files

- Remove self-monitoring project migration files.

lib/gitlab/background_migration/add_gitlab_instance_administration_project.rb

-# frozen_string_literal: true
-# rubocop:disable Style/Documentation
-
-module Gitlab
-  module BackgroundMigration
-    class AddGitlabInstanceAdministrationProject
-      def perform
-        Rails.logger.info("Creating Gitlab instance administration project") # rubocop:disable Gitlab/RailsLogger
-
-        Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService.new.execute!
-      end
-    end
-  end
-end

spec/lib/gitlab/background_migration/add_gitlab_instance_administration_project_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe Gitlab::BackgroundMigration::AddGitlabInstanceAdministrationProject, :migration, schema: 20190725080128 do
-  let(:application_settings) { table(:application_settings) }
-  let(:users)                { table(:users) }
-  let(:projects)             { table(:projects) }
-  let(:namespaces)           { table(:namespaces) }
-  let(:members)              { table(:members) }
-
-  let(:service_class) do
-    Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService
-  end
-
-  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 'perform' do
-    context 'without application_settings' do
-      it 'does not fail' do
-        subject.perform
-
-        expect(Project.count).to eq(0)
-      end
-    end
-
-    context 'without admin users' do
-      let!(:application_setting) { application_settings.create! }
-
-      it 'does not fail' do
-        subject.perform
-
-        expect(Project.count).to eq(0)
-      end
-    end
-
-    context 'with admin users' do
-      let(:project) { Project.last }
-      let(:group) { Group.last }
-      let!(:application_setting) { application_settings.create! }
-      let!(:user) { users.create!(admin: true, email: 'admin1@example.com', projects_limit: 10, state: :active) }
-
-      before do
-        stub_application_setting(allow_local_requests_from_web_hooks_and_services: true)
-      end
-
-      shared_examples 'has prometheus service' do |listen_address|
-        it do
-          subject.perform
-
-          prometheus = project.prometheus_service
-          expect(prometheus).to be_persisted
-          expect(prometheus).not_to eq(nil)
-          expect(prometheus.api_url).to eq(listen_address)
-          expect(prometheus.active).to eq(true)
-          expect(prometheus.manual_configuration).to eq(true)
-        end
-      end
-
-      it_behaves_like 'has prometheus service', 'http://localhost:9090'
-
-      it 'creates GitLab Instance Administrator group' do
-        subject.perform
-
-        expect(group).to be_persisted
-        expect(group.name).to eq('GitLab Instance Administrators')
-        expect(group.path).to start_with('gitlab-instance-administrators')
-        expect(group.path.split('-').last.length).to eq(8)
-        expect(group.visibility_level).to eq(service_class::VISIBILITY_LEVEL)
-      end
-
-      it 'creates project with internal visibility' do
-        subject.perform
-
-        expect(project.visibility_level).to eq(Gitlab::VisibilityLevel::INTERNAL)
-        expect(project).to be_persisted
-      end
-
-      it 'creates project with correct name and description' do
-        subject.perform
-
-        path = 'administration/monitoring/gitlab_instance_administration_project/index'
-        docs_path = Rails.application.routes.url_helpers.help_page_path(path)
-
-        expect(project.name).to eq(service_class::PROJECT_NAME)
-        expect(project.description).to eq(
-          'This project is automatically generated and will be used to help monitor this GitLab instance. ' \
-          "[More information](#{docs_path})"
-        )
-        expect(File).to exist("doc/#{path}.md")
-      end
-
-      it 'adds all admins as maintainers' do
-        admin1 = users.create!(admin: true, email: 'admin2@example.com', projects_limit: 10, state: :active)
-        admin2 = users.create!(admin: true, email: 'admin3@example.com', projects_limit: 10, state: :active)
-        users.create!(email: 'nonadmin1@example.com', projects_limit: 10, state: :active)
-
-        subject.perform
-
-        expect(project.owner).to eq(group)
-        expect(group.members.collect(&:user).collect(&:id)).to contain_exactly(user.id, admin1.id, admin2.id)
-        expect(group.members.collect(&:access_level)).to contain_exactly(
-          Gitlab::Access::OWNER,
-          Gitlab::Access::MAINTAINER,
-          Gitlab::Access::MAINTAINER
-        )
-      end
-
-      it 'saves the project id' do
-        subject.perform
-
-        application_setting.reload
-        expect(application_setting.instance_administration_project_id).to eq(project.id)
-      end
-
-      it 'does not fail when a project already exists' do
-        group = namespaces.create!(
-          path: 'gitlab-instance-administrators',
-          name: 'GitLab Instance Administrators',
-          type: 'Group'
-        )
-        project = projects.create!(
-          namespace_id: group.id,
-          name: 'GitLab Instance Administration'
-        )
-
-        admin1 = users.create!(admin: true, email: 'admin4@example.com', projects_limit: 10, state: :active)
-        admin2 = users.create!(admin: true, email: 'admin5@example.com', projects_limit: 10, state: :active)
-
-        members.create!(
-          user_id: admin1.id,
-          source_id: group.id,
-          source_type: 'Namespace',
-          type: 'GroupMember',
-          access_level: GroupMember::MAINTAINER,
-          notification_level: NotificationSetting.levels[:global]
-        )
-        members.create!(
-          user_id: admin2.id,
-          source_id: group.id,
-          source_type: 'Namespace',
-          type: 'GroupMember',
-          access_level: GroupMember::MAINTAINER,
-          notification_level: NotificationSetting.levels[:global]
-        )
-
-        stub_application_setting(instance_administration_project: project)
-
-        subject.perform
-
-        expect(Project.last.id).to eq(project.id)
-        expect(Group.last.id).to eq(group.id)
-      end
-
-      context 'when local requests from hooks and services are not allowed' do
-        before do
-          stub_application_setting(allow_local_requests_from_web_hooks_and_services: false)
-        end
-
-        it_behaves_like 'has prometheus service', 'http://localhost:9090'
-
-        it 'does not overwrite the existing whitelist' do
-          application_setting.update!(outbound_local_requests_whitelist: ['example.com'])
-
-          subject.perform
-
-          application_setting.reload
-          expect(application_setting.outbound_local_requests_whitelist).to contain_exactly(
-            'example.com', 'localhost'
-          )
-        end
-      end
-
-      context 'with non default prometheus address' do
-        let(:prometheus_settings) do
-          {
-            enable: true,
-            listen_address: 'https://localhost:9090'
-          }
-        end
-
-        it_behaves_like 'has prometheus service', 'https://localhost:9090'
-      end
-
-      context 'when prometheus setting is not present in gitlab.yml' do
-        before do
-          allow(Gitlab.config).to receive(:prometheus).and_raise(Settingslogic::MissingSetting)
-        end
-
-        it 'does not fail' do
-          subject.perform
-
-          expect(project.prometheus_service).to be_nil
-        end
-      end
-
-      context 'when prometheus setting is disabled in gitlab.yml' do
-        let(:prometheus_settings) do
-          {
-            enable: false,
-            listen_address: 'localhost:9090'
-          }
-        end
-
-        it 'does not configure prometheus' do
-          subject.perform
-
-          expect(project.prometheus_service).to be_nil
-        end
-      end
-
-      context 'when prometheus listen address is blank in gitlab.yml' do
-        let(:prometheus_settings) { { enable: true, listen_address: '' } }
-
-        it 'does not configure prometheus' do
-          subject.perform
-
-          expect(project.prometheus_service).to be_nil
-        end
-      end
-    end
-  end
-end