Add rebase merge request setting to project settings page.

app/assets/javascripts/project_new.js.coffee

@@ -23,3 +23,8 @@ class @ProjectNew
         $('#project_issues_tracker_id').attr('disabled', 'disabled')
       else
         $('#project_issues_tracker_id').removeAttr('disabled')
+
+    $("#project_merge_requests_enabled").change ->
+      checked = $(this).prop("checked")
+      $("#project_merge_requests_template").prop "disabled", not checked
+      $("#project_merge_requests_rebase_enabled").prop "disabled", not checked

app/views/projects/edit.html.haml

@@ -66,6 +66,13 @@
                   = f.check_box :merge_requests_enabled
                   %span.descr Submit changes to be merged upstream.
 
+            .form-group
+              = f.label :merge_requests_rebase_enabled, "Merge Requests Rebase", class: 'control-label'
+              .col-sm-10
+                .checkbox
+                  = f.check_box :merge_requests_rebase_enabled
+                  %span.descr Allows rebasing of merge requests before merging.
+
             .form-group
               = f.label :merge_requests_template, class: 'control-label' do
                 Merge request template