#In Rails 4.1, the following modification of Anatortoise House's reply works:

user = User.new
user.password = SecureRandom.hex #some random unguessable string
raw_token, hashed_token = Devise.token_generator.generate(User, :reset_password_token)
user.reset_password_token = hashed_token
user.reset_password_sent_at = Time.now.utc
user.email = 'user@usercompany.com'
user.save!
# Use a mailer you've written, such as:
AccountMailer.set_password_notice(user, raw_token).deliver

The email view has this link:

www.oursite.com/users/password/edit?initial=true&reset_password_token=<%= @raw_token %>