title: Laravel form model binding for many to many select input
body: <p>I have a many to many relationship between <code>clients</code> and <code>assets</code>.
  For my edit client form I have multi-select box with which the user can select several <code>assets</code> to attach to a client. The form is using model-binding so it automatically populates the fields with the existing client data.</p>
  
  <p>The model binding works for all fields in the form except the multi-select. Here is a snippet from my view:</p>
  
  <pre><code>{{ Form::model($client, ['route' =&gt; ['clients.update', $client-&gt;id], 'class' =&gt; '', 'method' =&gt; 'put']) }}
  
  {{ Form::label('name', 'Name', $label_attributes) }}
  {{ Form::text('name', null, array('class'=&gt;'form-control')) }}
  
  {{ Form::label('assets', 'Client Benchmarks (Select multiple)', $label_attributes) }}
  {{ Form::select('assets[]', $assets, null, array('multiple' =&gt; true, 'class' =&gt; 'form-control')); }}
  </code></pre>
  
  <p>When I submit the form the relationship saves the data successfully via the <code>sync</code> method in my controller (<code>update</code> method):</p>
  
  <pre><code>$client = Client::find($id);
  $client-&gt;name = Input::get('name');    
  $assets = Input::has('assets') ? Input::get('assets') : array();
  $client-&gt;assets()-&gt;sync($assets);
  $client-&gt;save();
  </code></pre>
  
  <p>Also, if I output the client assets directly they are accessible in the model collection in my form view:</p>
  
  <pre><code>&lt;?php print_r($client-&gt;assets); ?&gt;
  </code></pre>
  
  <p>How can I get the form to populate the select box with the existing selections?</p>