title: Skip email validation for omniauth-twitter on devise 2.0
body: <p>I'm using devise 2.0 and gem <a href="https://github.com/arunagw/omniauth-twitter">omniauth-twitter</a></p>
  
  <p>The problem is that twitter does not send an email in response, so the model user of my application validates that there is an email and I get the following error in the callback:</p>
  
  <pre><code>Email can't be blank
  </code></pre>
  
  <p>I have this in my <strong>user.rb</strong> model:</p>
  
  <pre><code>#config omniauth twitter
  def self.find_for_twitter_oauth(access_token, signed_in_resource = nil)
      data = access_token.extra.raw_info
      if user = User.where(:username =&gt; data.screen_name).first
          user
      else
          User.create!(:username =&gt; data.screen_name, :password =&gt; Devise.friendly_token)
      end
  end
  </code></pre>
  
  <p>and I have this in my <strong>omniauth_callbacks_controller.rb</strong></p>
  
  <pre><code>  def twitter
      @user = User.find_for_twitter_oauth(request.env["omniauth.auth"], current_user)
      if @user.persisted?
        flash[:notice] = I18n.t "devise.omniauth_callbacks.success", :kind =&gt; "Twitter"
        sign_in_and_redirect @user, :event =&gt; :authentication
      else
        # http://stackoverflow.com/questions/7117200/devise-for-twitter-cookie-overflow-error
        session["devise.twitter_data"] = request.env["omniauth.auth"].except('extra')
        redirect_to new_user_registration_url
      end
     end
  </code></pre>
  
  <p>I want force to user to give a email address for send newsletter, advertirser...etc</p>
  
  <p><strong>How can I fix this problem?</strong></p>
  
  <p>Thank you!</p>