Make nprogress color to red

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/main/variables.scss

@@ -46,4 +46,4 @@ $deleted: #f77;
 /**
  * NProgress customize
  */
-$nprogress-color: #3498db;
+$nprogress-color: #c0392b;