title: Stripe subscriptions do not work whichever version of the api I use
body: <p>Hi I am trying to change my payment method to use stripe. I am creating a plan and a customer and subscriptions for the customer using the code,</p>
  
  <pre><code>    \Stripe\Stripe::setApiKey("stripe api key");                                    
      $plan = \Stripe\Plan::create(array(
        "name" =&gt; $randomString,
        "id" =&gt; $randomString,
        "interval" =&gt; "month",
        "currency" =&gt; "usd",
        "amount" =&gt; $amtincents,
      ));
      \Stripe\Stripe::setApiKey("stripe api key");                                    
      $cust = \Stripe\Customer::create(array(
                "email" =&gt; $emailval,
              ));
      $custid = $cust-&gt;id;
      \Stripe\Stripe::setApiKey("stripe api key");                                    
      \Stripe\Subscription::create(array(
        "customer" =&gt; $custid,
        "plan" =&gt; $randomString,
      ));
  </code></pre>
  
  <p>The plan and customer get created but no matter which version of the stripe api I use I get the error 'Method \Stripe\Subscription not found' when I try to subscribe the customer to the plan. Any help would be appreciated.</p>