Add filters on budget investments index page

Now it's easier to change the investments filter. Previously we had to
go back to the budget index page, change the filter there, and then
select one heading.

Now the links to change the current filter in the budget index page
aren't needed anymore.

app/assets/javascripts/forms.js

@@ -8,8 +8,8 @@
         }
       });
     },
-    submitOnChange: function() {
-      $("body").on("change", ".js-submit-on-change", function() {
+    submitOnChange: function(selector) {
+      $("body").on("change", selector, function() {
         $(this).closest("form").submit();
         return false;
       });
@@ -58,7 +58,7 @@
     },
     initialize: function() {
       App.Forms.disableEnter();
-      App.Forms.submitOnChange();
+      App.Forms.submitOnChange(".js-submit-on-change");
       App.Forms.toggleLink();
       App.Forms.synchronizeInputs();
       App.Forms.hideOrShowFieldsAfterSelection();