InvitedUser for Devise > 3.0

invitation.html.erb

<p><%= t('.salutation', first_name: @user.first_name, last_name: @user.last_name) %>,</p>

<p><%= t('.instruction') %></p>

<p><%= link_to main_app.edit_user_password_url(@user, :reset_password_token => @token),
               main_app.edit_user_password_url(@user, :reset_password_token => @token) %></p>

<p><%= t('.ending') %></p>

<p><%= t('.greeting') %></p>

invited_user.rb

# Specialized User class containing invitation logic used by in the
# users admin.
class InvitedUser < User
  before_create :prepare_invitation
  after_create :send_invitation

  def send_invitation!
    prepare_invitation
    self.save(:validate => false)
    send_invitation
  end

  private

  def generate_reset_password_token
    raw, enc = Devise.token_generator.generate(self.class, :reset_password_token)

    self.reset_password_token   = enc
    self.reset_password_sent_at = Time.now.utc
    raw
  end

  def password_required?
    false
  end

  def prepare_invitation
    @token = generate_reset_password_token
  end

  def send_invitation
    UserMailer.invitation('user_id' => id, 'password_token' => @token).deliver
  end
end

Since Devise no longer stores the unencrypted reset token, we have to pass it explicitly to the mailer template.