Make current_budget accessible in controller and views

spec/controllers/application_controller_spec.rb

@@ -0,0 +1,19 @@
+require 'rails_helper'
+
+describe ApplicationController do
+
+  describe "#current_budget" do
+
+    it "returns the last budget that is not in draft phase" do
+      old_budget      = create(:budget, phase: "finished",  created_at: 2.years.ago)
+      previous_budget = create(:budget, phase: "accepting", created_at: 1.year.ago)
+      current_budget  = create(:budget, phase: "accepting", created_at: 1.month.ago)
+      next_budget     = create(:budget, phase: "drafting",  created_at: 1.week.ago)
+
+      budget = subject.instance_eval{ current_budget }
+      expect(budget).to eq(current_budget)
+    end
+
+  end
+
+end