make WorkerItemView.display rely on the model more

assets/scripts/app/models/worker.coffee

@@ -25,6 +25,10 @@ require 'travis/model'
     Travis.Job.find @get('job_id')
   ).property('jobId')
 
+  jobNumber: (->
+    @get('payload.job.number')
+  ).property('jobNumber')
+
   repoData: (->
     { id: @get('repoId'), slug: @get('repoSlug') }
   ).property('repoSlug', 'repoId')

assets/scripts/app/views/sidebar.coffee

@@ -67,12 +67,9 @@
     display: (->
       name = (@get('worker.name') || '').replace('travis-', '')
       state = @get('worker.state')
-      payload = @get('worker.payload')
 
-      if state == 'working' && payload?.repository && payload?.job
-        repo = @get('worker.repoSlug')
-        number = ' #' + payload.job.number
-        "<span class='name'>#{name}: #{repo}</span> #{number}".htmlSafe()
+      if state == 'working'
+        "<span class='name'>#{name}: #{@get('worker.repoSlug')}</span> ##{@get('worker.jobNumber')}".htmlSafe()
       else
         "#{name}: #{state}"
     ).property('worker.state')