config/initializers/stripe.rb

require 'stripe/model'

if Rails.env.production?
  Stripe.api_key = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
  STRIPE_PUBLISHABLE_KEY = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
else
  Stripe.api_key = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
  STRIPE_PUBLISHABLE_KEY = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
end

STRIPE_PLAN_ID = "some-awesome-plan"
STRIPE_TRIAL_PERIOD = 1.month

app/controllers/stripe_controller.rb

class StripeController < ApplicationController
  def webhook
    Account.subscription_event(params)
    head :ok
  end
end

app/controllers/accounts_controller.rb

class AccountsController < ApplicationController
  def cancel
    current_account.subscription_cancel!
    redirect_to settings_account_path, :notice => "Your account has been canceled."
  end

  def reactivate
    current_account.subscription_reactivate!
    redirect_to settings_account_path, :notice => "Your account has been reactivated."
  end
end

app/views/accounts/form.html.erb

You need to provide the following fields in your form:

• text_field_tag :credit_card_number, nil, :name => ""
• f.hidden_field :credit_card_token, :value => ""
• f.date_select :credit_card_expires_on, :start_year => Date.today.year, :add_month_numbers => true, :order => [:month, :year]

It doesn't matter what resource these form fields are on, if they use the above names the following JS will find them.

<script type="text/javascript" src="https://js.stripe.com/v1/"></script>
<script type="text/javascript">
  Stripe.setPublishableKey('<%= STRIPE_PUBLISHABLE_KEY %>');

  $(document).ready(function() {
    $("form.user_edit").submit(function(event) {
      var form = $(this);
      form.find(".billing-errors").html("");
      if(form.find('#credit_card_number').val()) {
        form.find('[type=submit]').attr("disabled", "disabled");
        Stripe.createToken({
          number: form.find('[id*=credit_card_number]').val(),
          exp_month: form.find('[id*=credit_card_expires_on_2i]').val(),
          exp_year: form.find('[id*=credit_card_expires_on_1i]').val(),
          coupon: form.find('[name*=coupon]').val()
        }, function(status, response) {
          if (response.error) {
            form.find(".billing-errors").html(response.error.message);
            form.find('[type=submit]').removeAttr("disabled");
          } else {
            form.find("[name*=credit_card_token]").val(response['id']);
            form.get(0).submit();
          }
        });
        return false;
      }
    });
  });
</script>