add timestamp columns to tables

app/Models/Bidders.php

@@ -16,9 +16,16 @@ class Bidders extends Model
       'bidder_zip',
       'bidder_phone',
       'bidder_email',
-      'bidder_assigned_number'
+      'bidder_assigned_number',
+      'created_at',
+      'updated_at'
     ];
 
+    protected $dates = [
+      'created_at',
+      'updated_at'
+    ];
+    
     public function checkout()
     {
       return $this->hasMany('App\Models\Checkout', 'bidder_num', 'idbidders');

app/Models/Checkout.php

@@ -13,7 +13,14 @@ class Checkout extends Model
     'payment_method',
     'check_number',
     'cc_transaction',
-    'cc_amount'
+    'cc_amount',
+    'created_at',
+    'updated_at'
+  ];
+
+  protected $dates = [
+  'created_at',
+  'updated_at'
   ];
 
   public function bidders()

app/Models/Items.php

@@ -11,9 +11,16 @@ class Items extends Model
     'item_desc',
     'item_min_bid',
     'item_est_value',
-    'item_assigned_num'
+    'item_assigned_num',
+    'created_at',
+    'updated_at'
   ];
 
+  protected $dates = [
+  'created_at',
+  'updated_at'
+  ];
+  
   public function winningBids()
   {
     return $this->belongsTo('App\Models\WinningBids', 'winning_item_num', 'iditems');

app/Models/PaymentMethods.php

@@ -8,7 +8,14 @@ class PaymentMethods extends Model
 {
   protected $table = 'payment_methods';
   protected $fillable = [
-    'pm_name'
+    'pm_name',
+    'created_at',
+    'updated_at'
+  ];
+
+  protected $dates = [
+    'created_at',
+    'updated_at'
   ];
 
   public function checkout()

app/Models/WinningBids.php

@@ -10,7 +10,14 @@ class WinningBids extends Model
   protected $fillable = [
     'winning_bidder_num',
     'winning_cost',
-    'winning_item_num'
+    'winning_item_num',
+    'created_at',
+    'updated_at'
+  ];
+
+  protected $dates = [
+    'created_at',
+    'updated_at'
   ];
 
   public function items()