title: Typegoose enum arrayProp returns an error: Type is not a constructor
body: <p>I have got a problem with the definition of my array schema. So basically, what I wanted to achieve is a single user Model with a property called games, that holds an array of games user is playing. The problem is I have got defined games as enum:</p>
  <pre><code>module Constants {
      export enum Games {
          LOL = 'League Of Legends',
      }
  }
  </code></pre>
  <p>export {Constants};</p>
  <p>And now, when I try to attach it to the schema model like that:</p>
  <pre><code>@arrayProp({ required: true, items: Constants.Games })
  games: Constants.Games[];
  </code></pre>
  <p>I receive an error (after a successful compilation, just before the server start)</p>
  <pre><code>^ const instance = new Type();
  TypeError: Type is not a constructor
      at baseProp (C:\Users\Borys\Desktop\lft\backend\node_modules\typegoose\lib\prop.js:114:22)
      at C:\Users\Borys\Desktop\lft\backend\node_modules\typegoose\lib\prop.js:177:9
      at DecorateProperty (C:\Users\Borys\Desktop\lft\backend\node_modules\reflect-metadata\Reflect.js:553:33)
      at Object.decorate (C:\Users\Borys\Desktop\lft\backend\node_modules\reflect-metadata\Reflect.js:123:24)
      at __decorate (C:\Users\Borys\Desktop\lft\backend\build\dataModel\User.js:4:92)
      at Object.&lt;anonymous&gt; (C:\Users\Borys\Desktop\lft\backend\build\dataModel\User.js:64:1)
  </code></pre>
  <p>I have read a little bit about this error, but it relates to the required option for items/itemsRef I tried removing required, using enum, using even itemsRef and relating to the different set of documents but none of these worked for me.</p>
  <p>Anyone could help/relate?</p>