title: how to use braintree with rails and activemerchant
body: <p>I have a simple rails website to which I need to add a payments gateway now.  I see a <a href="http://railscasts.com/episodes/145-integrating-active-merchant">railscast on integrating activemerchant with paypal</a> but I wanted to use braintree instead. </p>
  
  <p>I am unable to find any tutorials that show how braintree can be integrated to a rails app end to end.  I see that people have good things to say about braintree but how about a tutorial?  </p>
  
  <p>Has someone used this payment gateway for their rails application? Would it be similar to the railscasts with paypal...just replace paypal with braintree?</p>