Add migration to migrate alertservices

db/migrate/20201027002551_migrate_services_to_http_integrations.rb

+# frozen_string_literal: true
+
+# See https://docs.gitlab.com/ee/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class MigrateServicesToHttpIntegrations < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  ALERT_SERVICE_TYPE = 'AlertsService'
+  SERVICE_NAMES_IDENTIFIER = {
+    name: 'Legacy Endpoint',
+    identifier: 'legacy'
+  }
+
+  class HttpIntegration < ActiveRecord::Base
+    self.table_name = 'alert_management_http_integrations'
+  end
+
+  # For each Alerts service,
+  # Create the matching HttpIntegration
+  def up
+    HttpIntegration.reset_column_information
+
+    sql = <<~SQL
+      SELECT * FROM services
+      JOIN alerts_service_data
+      ON (services.id = alerts_service_data.service_id)
+      WHERE type = '#{ALERT_SERVICE_TYPE}'
+    SQL
+
+    select_all(sql).each do |alerts_service|
+      HttpIntegration.create!(
+        project_id: alerts_service['project_id'],
+        name: SERVICE_NAMES_IDENTIFIER[:name],
+        endpoint_identifier: SERVICE_NAMES_IDENTIFIER[:identifier],
+        encrypted_token: alerts_service['encrypted_token'],
+        encrypted_token_iv: alerts_service['encrypted_token_iv'],
+        active: alerts_service['active']
+      )
+    end
+  end
+
+  def down
+    # NO-OP
+  end
+end

db/schema_migrations/20201027002551

+34e357b739235d627e543e1bc7202e0cf26f5b1ca8021bb25357e29e883f785b
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