ruby on rails - ArgumentError in Users::Registrations#create -

i making user-sign_up interface using devise gem

missing host link to! please provide :host parameter, set default_url_options[:host], or set :only_path true

 <p>you can confirm account email through link below:</p>  <p><%= link_to 'confirm account', confirmation_url(@resource, confirmation_token: @token) %></p> 

you need set host variable application url. in environment.rb file

config.action_controller.default_url_options = { host: application url' }