Adds reference to the merge request in the commit column

app/assets/stylesheets/pages/environments.scss

@@ -39,4 +39,10 @@
     width: 20px;
     text-align: center;
   }
+  
+  .branch-commit {
+    .commit-id {
+      margin-right: 0px;
+    }
+  }
 }

app/views/projects/deployments/_commit.html.haml

+- merge_request = deployment.deployable.try(:merge_request)
+
 %div.branch-commit
   - if deployment.ref
     .icon-container
@@ -6,6 +8,10 @@
   .icon-container
     = custom_icon("icon_commit")
   = link_to deployment.short_sha, namespace_project_commit_path(@project.namespace, @project, deployment.sha), class: "commit-id monospace"
+  
+  - if merge_request
+    %span in
+    = link_to_gfm merge_request.to_reference, merge_request_path(merge_request)
 
   %p.commit-title
     %span