Fix order loading custom styles

We have to load the custom styles last so they actually override what we
do.

app/assets/stylesheets/application.scss

@@ -20,7 +20,6 @@
 @import "notification_item";
 @import "community";
 @import "stats";
-@import "custom";
 @import "c3";
 @import "annotator.min";
 @import "amsify.suggestags";
@@ -38,3 +37,5 @@
 @import "sdg_management/*";
 @import "sdg_management/**/*";
 @import "widgets/**/*";
+
+@import "custom";