add job creation error

use it on creation error, update tests

src/constants/events.js

@@ -1,8 +1,8 @@
 export default {
   EVENT_QUEUE_ERROR: 'error',
-  EVENT_JOB_CREATED: 'job:created',
   EVENT_JOB_ERROR: 'job:error',
-  EVENT_WORKER_ERROR: 'worker:error',
+  EVENT_JOB_CREATED: 'job:created',
+  EVENT_JOB_CREATE_ERROR: 'job:creation error',
   EVENT_WORKER_COMPLETE: 'worker:job complete',
   EVENT_WORKER_JOB_CLAIM_ERROR: 'worker:claim job error',
   EVENT_WORKER_JOB_SEARCH_ERROR: 'worker:pending jobs error',

src/job.js

@@ -62,7 +62,7 @@ export default class Job extends events.EventEmitter {
     })
     .catch((err) => {
       this.debug('Job creation failed', err);
-      this.emit(contstants.EVENT_JOB_ERROR, err);
+      this.emit(contstants.EVENT_JOB_CREATE_ERROR, err);
     });
   }