public function process(Plan $plan)
    {
        // Activate the plan and save
        $shop = ShopifyApp::shop();
        $bp = new BillingPlan($shop, $plan);
        $bp->setChargeId(Request::query('charge_id'));
        $bp->activate();
        $bp->save();

        // All good, update the shop's plan and take them off freemium (if applicable)
        $shop->update([
            'freemium' => false,
            'plan_id'  => $plan->id,
        ]);

        // Go to homepage of app
        return Redirect::route('home')->with('success', 'billing');
    }