title: Eloquent hasOne relationship return null
body: <p>I have 2 models Admin and Subscription</p>
  
  <p>Model Admin.php</p>
  
  <pre><code>public function subscription() {
      return $this-&gt;hasOne('App\Subscription','admin_id','id'); 
  }
  </code></pre>
  
  <p>Model Subscription.php</p>
  
  <pre><code>public function payer() {
       return $this-&gt;belongsTo('App\Admin','admin_id','id');
  }
  </code></pre>
  
  <p>When i try to get payer of the subscription it returns null.
  I am getting a payer like this.</p>
  
  <p>In Controller.php</p>
  
  <pre><code>$subscriptions=Subscription::all();
  
  foreach ($subscriptions as $subscription) {
      dd($subscription-&gt;payer);
  }
  </code></pre>
  
  <p>Please give me a solution. I tried and change everything it's still not working.</p>
  
  <p>This is my migrations</p>
  
  <p>Subscription Table</p>
  
  <pre><code>id  int(10) unsigned Auto Increment  
  subscription_type   varchar(191) NULL    
  expiry_date timestamp NULL   
  status  varchar(191) [required]      
  admin_id    varchar(191)     
  created_at  timestamp NULL   
  updated_at  timestamp NULL
  </code></pre>
  
  <p>Admin Table</p>
  
  <pre><code>id  int(10) unsigned Auto Increment  
  name    varchar(191)     
  email   varchar(191)     
  password    varchar(191)     
  remember_token  varchar(100) NULL    
  created_at  timestamp NULL   
  updated_at  timestamp NULL
  </code></pre>