Add budget investment translations

Also fix sort_by_title method [1]

[1] Use ruby sort instead of active record order scope because Globalize
does not provide a way to search over all available fallbacks when
translation for current locale does not exist.

db/migrate/20181214094002_add_budget_investment_translations.rb

@@ -0,0 +1,15 @@
+class AddBudgetInvestmentTranslations < ActiveRecord::Migration[4.2]
+  def self.up
+    Budget::Investment.create_translation_table!(
+      {
+        title:               :string,
+        description:         :text
+      },
+      { migrate_data: true }
+    )
+  end
+
+  def self.down
+    Budget::Investment.drop_translation_table!
+  end
+end