autocomplete for zip and city

app/controllers/cities_autocomplete_controller.rb

@@ -0,0 +1,13 @@
+require 'CSV'
+class CitiesAutocompleteController < ApplicationController
+  skip_before_action :verify_authenticity_token
+
+  def index
+    @cities = CSV.read Rails.root.join('db', 'plz_ch.csv')
+
+    @cities = @cities.select { |city| city.first =~ /#{params[:query]}/i || city.last =~ /#{params[:query]}/i  }
+    @cities = @cities.map { |city| { plz: city.first, city: city.last } }
+
+    render json: @cities.uniq
+  end
+end