Use GitHub user ids instead of usernames for authentication

Otherwise, renaming a GitHub account could allow someone else
to gain access to a CDB account.

app/blueprints/admin/actions.py

@@ -28,6 +28,7 @@ from app.tasks.emails import send_pending_digests
 from app.tasks.forumtasks import import_topic_list, check_all_forum_accounts
 from app.tasks.importtasks import import_repo_screenshot, check_zip_release, check_for_updates, update_all_game_support, \
 	import_languages
+from app.tasks.usertasks import import_github_user_ids
 from app.utils import add_notification, get_system_user
 
 actions = {}
@@ -289,6 +290,13 @@ def do_send_pending_digests():
 	send_pending_digests.delay()
 
 
+@action("Import user ids from GitHub")
+def do_import_github_user_ids():
+	task_id = uuid()
+	import_github_user_ids.apply_async((), task_id=task_id)
+	return redirect(url_for("tasks.check", id=task_id, r=url_for("admin.admin_page")))
+
+
 @action("DANGER: Delete removed packages")
 def del_removed_packages():
 	query = Package.query.filter_by(state=PackageState.DELETED)