title: Braintree vault not storing payment methods
body: <p>My sandbox account doesn't store payment methods for customer in their vault. I am creating a customer object using:</p>
  
  <pre><code>def create_customer
    result = Braintree::Customer.create(
      :first_name =&gt; params[:first_name],
      :last_name =&gt; params[:last_name],
      :email =&gt; params[:email],
      :phone =&gt; params[:phone]
      )
    if result.success?
      render :json =&gt; {'result' =&gt; result.customer.id}
    else
      render :json =&gt; {'errors' =&gt; result.errors}, :status =&gt; 400
    end
  end
  </code></pre>
  
  <p>and then storing the <code>customer_id</code> in my database for later use.</p>
  
  <p>When creating client_token I am sending the same <code>customer_id</code> to the API. Here is the code for creating client_token:</p>
  
  <pre><code>def client_token
    token = Braintree::ClientToken.generate(
      :customer_id =&gt; params[:customer_id]
      )
    render :json =&gt; {"token" =&gt; token}
  end
  </code></pre>