Require custom JavaScript after everything else

This way we make sure the custom JavaScript will overwrite anything in
the original code.

app/assets/javascripts/application.js

@@ -92,7 +92,6 @@
 //= require documentable
 //= require imageable
 //= require tree_navigator
-//= require custom
 //= require tag_autocomplete
 //= require polls_admin
 //= require leaflet
@@ -114,6 +113,7 @@
 //= require_tree ./admin
 //= require_tree ./sdg
 //= require_tree ./sdg_management
+//= require custom
 //= require_tree ./custom
 
 var initialize_modules = function() {