fetch all countries via web service in rails in order to choose in a select_tag using http://api.worldbank.org

application_helper.rb

module ApplicationHelper
  def select_country
    countries = JSON.parse(open('http://api.worldbank.org/v2/es/countries?format=json&&per_page=250').read).last
    countries.map {|key, val|[key["name"], key["iso2Code"]] unless key["name"].blank? }.compact!
  end
end

view.html.erb

<%= form_for @client do|f| %>
  .
  .
  <td><%= f.label :country %></td>
  <td><%= f.select :country, options_for_select(select_country , "CO"), {:prompt => "Choose an option"}%></td>
  .
  .
<% end%>