title: AngularJS: passing boolean value to directive
body: <p>I can not pass <em>boolean value</em> to my directive.</p>
  
  <p>Here is my HMTL:</p>
  
  <pre><code>&lt;city-zip city="clientCity" zip="clientZip" requiredParam="'true'"&gt;&lt;/city-zip&gt;
  </code></pre>
  
  <p>And directive:</p>
  
  <pre><code>.directive('cityZip', function() {
      return {
          restrict: 'E',
          templateUrl: '../templates/templateCityZip.html',
          scope: {
              city: '=',
              zip: '='
          },
          controller: function($scope) {}
      }
  });
  </code></pre>
  
  <p>Any help would be much appreciated.</p>