title: Laravel 5.2 How to populate edit form with multiple select?
body: <p>I want to create a zone which contain few cities. So I decided to use jQuery Select2</p>
  
  <p>Here is my create form multiple selection</p>
  
  <pre><code>&lt;div class="form-group {{ $errors-&gt;has('cities') ? 'has-error' : '' }}"&gt;
                      &lt;label&gt;Tentukan Kota&lt;/label&gt;
                      &lt;select name="cities[]" class="city form-control" data-placeholder="Pilih Kota" style="width: 100%;" multiple="multiple"&gt;
                      @foreach($cities as $city)
                      &lt;option value="{{ $city-&gt;id }}"&gt;{{ $city-&gt;name }}&lt;/option&gt;
                      @endforeach
                      &lt;/select&gt;
  
                  &lt;/div&gt;
  </code></pre>
  
  <p>I can multiple select just like in documentation.</p>
  
  <p>Here is my controller which handle display create form</p>
  
  <pre><code>public function zone_create()
  {
      $cities = City::where('zone_id', null)-&gt;get();
      return view('backend.admin.pricings.zone_create', compact('cities'));
  }
  </code></pre>
  
  <p>The relationship is One Zone Has Many City.</p>
  
  <pre><code>class Zone extends Model
  {
      protected $fillable = [
          'name',    
      ];
  
      public function cities(){
          return $this-&gt;hasMany(City::class);    
      }
  }
  </code></pre>
  
  <p>The city belongs to zone</p>
  
  <pre><code>class City extends Model
  {
      protected $fillable = [
          'zone_id',
          'name',    
      ];
  
      public function zone(){
          return $this-&gt;belongsTo(Zone::class);    
      }
  }
  </code></pre>
  
  <p>Here is my edit method</p>
  
  <pre><code>public function edit($id)
  {
      $zone = Zone::find($id);
      $cities = City::all();
      return view('backend.admin.pricings.zone_edit', compact('zone', 'cities'));
  }
  </code></pre>
  
  <p>Here is my edit form so far             </p>
  
  <pre><code>&lt;div class="form-group {{ $errors-&gt;has('cities') ? 'has-error' : '' }}"&gt;
                      &lt;label&gt;Tentukan Kota&lt;/label&gt;
                      &lt;select name="cities[]" class="city form-control" data-placeholder="Pilih Kota" style="width: 100%;" multiple="multiple"&gt;
                      //load option from cities table
  //set selected the city belongs to zone
  //the other city which don't belong to zone still here for option
                      &lt;/select&gt;
  
                  &lt;/div&gt;
  </code></pre>
  
  <p>But how I can populate my edit form (multiple selection) with City belongs to zone?</p>