subscription.rb

class Subscription < ActiveRecord::Base
 belongs_to :user
 attr_accessible :user_id, :stripe_card_token


def save_with_payment(plan, email)
    if valid?
      customer = Stripe::Customer.create(description: 'ta@gmail.com', plan: '1', card: stripe_card_token)
      self.stripe_customer_token = customer.id
      save!
    end
  rescue Stripe::InvalidRequestError => e
    logger.error "Stripe error while creating customer: #{e.message}"
    errors.add :base, "There was a problem with your credit card."
    false
  end




end

subscriptions_controller.rb

def create
    @subscription = Subscription.new(params[:subscription])
    @user = User.new(params[:user])
        respond_to do |format|
          if   @user.save &&   @subscription.save_with_payment(plan, @user.email)
               @subscription.user_id = @user.id
               @subscription.save
          format.html { redirect_to pages_thankyou_url }
          else
       format.html { render action: "new"  }
              end
        end
 end

user.rb

class User < ActiveRecord::Base
  has_many :subscriptions
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable,
  # :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable, :confirmable  

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me

end