Update plugin doc

- This isn't being used right now, but it should be a first step towards 
having proper plugin documentation.

lib/plugins/case-converter.js

@@ -15,14 +15,12 @@ module.exports = function caseConverter(bookshelf) {
 
   /**
    * Monkey-patched Model class.
-   * @class Model
+   * @extends Model
    */
   bookshelf.Model = bookshelf.Model.extend({
 
     /**
-     * @method
      * @description Converts attribute keys to camel case when fetching data from the database.
-     * @override
      */
     parse: function(attrs) {
       return _.mapKeys(attrs, function(value, key) {