Update branch status with ajax call.

app/assets/javascripts/protected_branches.js.coffee

+$ ->
+  $(":checkbox").change ->
+    id = $(this).val()
+    checked = $(this).is(":checked")
+    url = $(this).data("url")
+    $.ajax
+      type: "PUT"
+      url: url
+      dataType: "json"
+      data:
+        id: id
+        developers_can_push: checked
+
+      success: ->
+        new Flash("Branch updated.", "notice")
+        location.reload true
+
+      error: ->
+        new Flash("Failed to update branch!", "alert")

app/controllers/projects/protected_branches_controller.rb

@@ -22,13 +22,14 @@ class Projects::ProtectedBranchesController < Projects::ApplicationController
        protected_branch.update_attributes(
         developers_can_push: params[:developers_can_push]
        )
-      flash[:notice] = 'Branch was successfully updated.'
-    else
-      flash[:alert] = 'Could not update the branch.'
-    end
-    respond_to do |format|
-      format.html { redirect_to project_protected_branches_path }
+      respond_to do |format|
+        format.json { render :json => protected_branch, status: :ok }
+      end
+    else
+      respond_to do |format|
+        format.json { render json: protected_branch.errors, status: :unprocessable_entity }
+      end
     end
   end