Heroku logs - email error

gistfile1.txt

2013-05-15T20:35:41.399417+00:00 app[web.1]:   Rendered devise/shared/_links.erb (0.6ms)
2013-05-15T20:35:41.399417+00:00 app[web.1]:   Rendered devise/registrations/new.html.erb within layouts/application (6.3ms)
2013-05-15T20:35:41.399417+00:00 app[web.1]: Completed 200 OK in 12ms (Views: 11.0ms | ActiveRecord: 0.0ms)
2013-05-15T20:35:41.400658+00:00 heroku[router]: at=info method=GET path=/users/sign_up host=bloccit.herokuapp.com fwd="65.206.21.165" dyno=web.1 connect=0ms service=25ms status=200 bytes=3289
2013-05-15T20:35:41.399417+00:00 app[web.1]: Processing by Devise::RegistrationsController#new as HTML
2013-05-15T20:35:41.882902+00:00 heroku[router]: at=info method=GET path=/assets/application-770fe5755077bd5022e97daf1c747e09.js host=bloccit.herokuapp.com fwd="65.206.21.165" dyno=web.1 connect=5ms service=357ms status=304 bytes=0
2013-05-15T20:35:49.243880+00:00 app[web.1]: Started POST "/users" for 65.206.21.165 at 2013-05-15 20:35:47 +0000
2013-05-15T20:35:50.492979+00:00 heroku[router]: at=info method=POST path=/users host=bloccit.herokuapp.com fwd="65.206.21.165" dyno=web.1 connect=3ms service=3484ms status=500 bytes=643
2013-05-15T20:35:50.494065+00:00 app[web.1]: 
2013-05-15T20:35:50.494065+00:00 app[web.1]:     5: <p><%= link_to 'Confirm my account', confirmation_url(@resource, :confirmation_token => @resource.confirmation_token) %></p>
2013-05-15T20:35:50.494065+00:00 app[web.1]:     4: 
2013-05-15T20:35:50.494065+00:00 app[web.1]:     3: <p>You can confirm your account email through the link below:</p>
2013-05-15T20:35:50.494065+00:00 app[web.1]: ActionView::Template::Error (Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true):
2013-05-15T20:35:50.494065+00:00 app[web.1]:     2: 
2013-05-15T20:35:50.494065+00:00 app[web.1]:   app/views/devise/mailer/confirmation_instructions.html.erb:5:in `_app_views_devise_mailer_confirmation_instructions_html_erb___1409885699918348305_49012240'
2013-05-15T20:35:50.494452+00:00 app[web.1]: Completed 500 Internal Server Error in 1234ms