automatically set to false when saving. (#13)

README.md

@@ -41,7 +41,7 @@ $id = $snowflake->next();
 ```
 # Usage with Eloquent
 Add the `Kra8\Snowflake\HasSnowflakePrimary` trait to your Eloquent model.
-This trait make type `snowflake` of primary key.  Don't forget to set the Auto increment property to false.
+This trait make type `snowflake` of primary key. Trait will automatically set $incrementing property to false.
 
 ``` php
 <?php
@@ -54,13 +54,6 @@ use Illuminate\Foundation\Auth\User as Authenticatable;
 class User extends Authenticatable
 {
     use HasSnowflakePrimary, Notifiable;
-
-    /**
-     * Indicates if the IDs are auto-incrementing.
-     *
-     * @var bool
-     */
-    public $incrementing = false;
 }
 ```
 

src/HasSnowflakePrimary.php

@@ -9,6 +9,7 @@ public static function bootHasSnowflakePrimary()
     {
         static::saving(function ($model) {
             if (is_null($model->getKey())) {
+                $model->setIncrementing(false);
                 $keyName    = $model->getKeyName();
                 $id         = app(Snowflake::class)->next();
                 $model->setAttribute($keyName, $id);