[2.x] Protect against duplication of customer (#234)

* Protect against duplication of customer

* wip

* Update ManagesCustomer.php

---------

Co-authored-by: Taylor Otwell <taylor@laravel.com>

Author: driesvints

src/Concerns/ManagesCustomer.php

@@ -45,6 +45,10 @@ public function createAsCustomer(array $options = [])
             $response = Cashier::api('POST', 'customers', $options)['data'];
         }
 
+        if (Cashier::$customerModel::where('paddle_id', $response['id'])->exists()) {
+            throw new LogicException("The Paddle customer [{$response['id']}] already exists in the database.");
+        }
+
         $customer = $this->customer()->make();
         $customer->paddle_id = $response['id'];
         $customer->name = $response['name'];

src/Concerns/PerformsCharges.php

@@ -30,6 +30,6 @@ public function checkout($prices, int $quantity = 1)
      */
     public function subscribe($prices, string $type = Subscription::DEFAULT_TYPE)
     {
-        return $this->checkout($prices, 1)->customData(['subscription_type' => $type]);
+        return $this->checkout($prices)->customData(['subscription_type' => $type]);
     }
 }