Mark job as error when it's not healthy

web/views/dashboard.haml

@@ -7,10 +7,15 @@
     %th Job
     %th Last performed at
     %th
+    %th
   - for job in @jobs
     %tr
       %td= job.job_id
       %td= job.last_performed_at || "—"
+      %td
+        - if job.healthy == false
+          %a{href: url("/job/#{job.id}")}
+            %span.label.label-danger Error
       %td
         %a{href: url("/job/#{job.id}")}
           Log

web/views/job.haml

@@ -5,4 +5,9 @@
 
 %h2
   "#{@job.job_id}" Log:
+
+- if @job.healthy == false
+  .alert.alert-danger{role: "alert"}
+    An error occurs during the last execution of this job. Check the log below for details.
+
 %pre= @job.log