Fix handling of team sync when a user already exists with the email address

test/fixtures.py

@@ -56,6 +56,9 @@ def init_db_path(tmpdir_factory):
   application.config.update(conf)
   application.config.update({"DB_URI": sqlitedb})
   initialize_database()
+
+  db.obj.execute_sql('PRAGMA foreign_keys = ON;')
+
   populate_database()
   close_db_filter(None)
   return str(sqlitedb_file)