Add approval voting to budgets

Co-Authored-By: Javi Martín <javim@elretirao.net>

spec/helpers/budgets_helper_spec.rb

@@ -0,0 +1,14 @@
+require "rails_helper"
+
+describe BudgetsHelper do
+  describe "#budget_voting_styles_select_options" do
+    it "provides vote kinds" do
+      types = [
+        ["Knapsack", "knapsack"],
+        ["Approval", "approval"]
+      ]
+
+      expect(budget_voting_styles_select_options).to eq(types)
+    end
+  end
+end