title: Swagger ui shows duplicate model variables
body: <p>Swagger-ui shows duplicate model variables when in edit and none edit mode. This happens to every single model shown on the ui have duplicate model variable. Not sure if this is due to using kotlin but its really frustrating and confusing. The duplicate variable seems to have $timefundcharity after each variable. </p>
  
  <p>Each model is also a MongoDb entity annotated with @Document</p>
  
  <p>Any help is welcome</p>
  
  <pre><code>{
    "charityId$charity": 0,
    "createdAt$charity": "2019-06-19T20:16:33.735Z",
    "id": 0,
    "id$charity": 0,
    "userId": 0,
    "userId$charity": 0,
    "charityId": 0,
    "createdAt": "2019-06-19T20:16:33.735Z"
  }
  </code></pre>
  
  <p><img src="https://i.imgur.com/O60SSWd.png" alt="Image of swagger-ui">
  <img src="https://imgur.com/fNmw8uY" alt="Image of swagger-ui model view"></p>
  
  <p>I have looked around the internet on how to resolve this but it seems no one really has come across this issue and thought i better reach out here.</p>
  
  <p>At first i thought maybe it was the swagger configuration but it doesn't seems to be that either as i have compared the configuration with other sources</p>
  
  <pre><code>@Document(collection = "CharityFollowers")
  @ApiModel
  data class CharityFollower
  (
          internal var userId: BigInteger,
          internal var charityId: BigInteger,
          internal var createdAt: LocalDateTime = LocalDateTime.now()
  ){
      @Id internal lateinit var id : BigInteger
  }
  </code></pre>
  
  <p>swagger config</p>
  
  <pre><code>@Bean
  fun productApi(): Docket {
          return Docket(DocumentationType.SWAGGER_12)
                  .select()
                  .apis(RequestHandlerSelectors.basePackage("com.martin.charity.controllers"))
                  .build()
                  .securityContexts(arrayListOf(securityContext()))
                  .securitySchemes(arrayListOf(this.securitySchema(), this.apiKey(), this.apiCookieKey()))
      }
  </code></pre>
  
  <p>I am expecting the result not to have duplicate model variables</p>