autocomplete for zip and city

spec/controllers/cities_autocomplete_controller_spec.rb

@@ -0,0 +1,12 @@
+require 'rails_helper'
+
+describe CitiesAutocompleteController do
+  describe 'GET index' do
+    it 'searchs for cities' do
+      get :index, query: 'spei', format: :js
+
+      result = JSON.parse response.body
+      expect(result).to eq [{ 'plz' => '9042', 'city' => 'Speicher' }, { 'plz' => '9037', 'city' => 'Speicherschwendi' }]
+    end
+  end
+end