title: GraphQL - Apollo - Android - Kotlin - Custom types are not getting generated even after specifying them in build.gradle
body: <p>I am using Apollo Client and Graph Ql for my project, I am trying to use <code>CustomTypeAdapter</code> and map one of the fields present in <code>schema</code> to a custom field. But Custom Type generated does not contain the value that I specify in <code>build.gradle</code>.</p>
  
  <p>Below is my app level <code>build.gradle</code></p>
  
  <pre><code> apollo {
          generateKotlinModels.set(true) // or false for Java models
          customTypeMapping = [
                  "PersonDetail": "com.task.databasepoc.models.Person"
          ]
      }
  </code></pre>
  
  <p>Below is my project level build.gradle:</p>
  
  <pre><code>dependencies {
          classpath "com.apollographql.apollo:apollo-gradle-plugin:2.0.3"
      }
  </code></pre>
  
  <p>Below is my <code>CustomTypeAdapter</code>:</p>
  
  <pre><code>object TypeAdapter : CustomTypeAdapter&lt;Person&gt; {
          override fun decode(value: CustomTypeValue&lt;*&gt;): Person {
              return value as Person
          }
  
          override fun encode(value: Person): CustomTypeValue&lt;*&gt; {
              return CustomTypeValue.fromRawValue(value)
          }
  
  
      }
  </code></pre>
  
  <p>I am trying build <code>ApolloClient</code> as shown below:</p>
  
  <pre><code>fun getApolloClient(): ApolloClient {
          val httpLoggingInterceptor = HttpLoggingInterceptor()
          httpLoggingInterceptor.level = HttpLoggingInterceptor.Level.BODY
  
          val okHttpClient = OkHttpClient.Builder()
              .addInterceptor(httpLoggingInterceptor)
              //.addInterceptor(AuthHeaderInterceptor(authStorageService))
              //.addInterceptorInterceptor(CorrelationIdInterceptor(correlationIdProvider))
              .connectTimeout(10000, TimeUnit.MILLISECONDS)
              .writeTimeout(30000, TimeUnit.MILLISECONDS)
              .readTimeout(30000, TimeUnit.MILLISECONDS)
              .build()
          return ApolloClient.builder()
              .serverUrl("serverUrl")
              .okHttpClient(okHttpClient)
              .addCustomTypeAdapter(CustomType.PersonDetail, TypeAdapter)
              .build()
      }
  </code></pre>
  
  <p><code>CustomType</code> class does not contain <code>PersonDetail</code>.</p>
  
  <p>I have tried <code>rebuilding</code>, <code>syncing</code> everything but no use.</p>
  
  <p>Can anyone please tell me what I am missing here?</p>