add cancelled status

src/helpers/constants.js

@@ -3,6 +3,7 @@ export const jobStatuses = {
   JOB_STATUS_PROCESSING: 'processing',
   JOB_STATUS_COMPLETED: 'completed',
   JOB_STATUS_FAILED: 'failed',
+  JOB_STATUS_CANCELLED: 'cancelled',
 };
 
 export default Object.assign({}, jobStatuses);