added credit limit seeder, it causes error when creating booking

app/Http/Controllers/BookingController.php

@@ -165,7 +165,12 @@ class BookingController extends Controller
         $rates = Rate::orderby('updated_at','desc')->first();
         $term = $request->input('term');
         $amount = $request->input("amount");    // in RMB
-        $creditLimit = SettingCredit::orderby('updated_at','desc')->first();
+		$creditLimit = SettingCredit::orderby('updated_at','desc')->first();
+
+		if (!$creditLimit){
+			return response()->json("Credit limit not set, please contact admin", 405);
+		}
+
         if($amount > $creditLimit->rmb_credit_limit){
             return response()->json("Exceed credit limit, need approved from admin", 401);
         }

database/seeds/CreditTableSeeder.php

@@ -0,0 +1,22 @@
+<?php
+
+use Illuminate\Database\Seeder;
+use Carbon\Carbon;
+
+class CreditTableSeeder extends Seeder
+{
+    /**
+     * Run the database seeds.
+     *
+     * @return void
+     */
+    public function run()
+    {
+        DB::table('setting_credits')->insert([
+            'rmb_credit_limit' => 20000,
+            'usd_credit_limit' => 20000,
+            'created_at' => Carbon::now()->format('Y-m-d H:i:s'),
+            'updated_at' => Carbon::now()->format('Y-m-d H:i:s'),
+        ]);
+    }
+}

database/seeds/DatabaseSeeder.php

@@ -16,5 +16,6 @@ class DatabaseSeeder extends Seeder
         $this->call(UserRoleSeeder::class);
         $this->call(RateTableSeeder::class);
         $this->call(BookTableSeeder::class);     
+        $this->call(CreditTableSeeder::class);  
     }
 }