Add description of useObjectMapperForRequestSerialization to codegen-options.md #912

Author: kobylynskyi

docs/codegen-options.md

@@ -59,6 +59,7 @@ See [DirectiveAnnotationsMapping](#option-directiveannotationsmapping)* |
 | `initializeNullableTypes`                             | Boolean                                                               | false                                                  | Adds a default null value to nullable arguments. Only supported in Kotlin.
 | `generateSealedInterfaces`                            | Boolean                                                               | false                                                  | This applies to generated interfaces on unions and interfaces. If true, generate sealed interfaces, else generate normal ones. It is only supported in Kotlin. |
 | `typesAsInterfaces`                                   | Set(String)                                                           | Empty                                                  | Types that must generated as interfaces should be defined here in format: `TypeName` or `@directive`. E.g.: `User`, `@asInterface`. |
+| `useObjectMapperForRequestSerialization`              | Set(String)                                                           | Empty                                                  | Fields that require serialization using `com.fasterxml.jackson.databind.ObjectMapper#writeValueAsString(Object)`. Values should be defined here in the following format: `GraphqlObjectName.fieldName` or `GraphqlTypeName`. If just type is specified, then all fields of this type will be serialized using ObjectMapper. E.g.: `["Person.createdDateTime", ZonedDateTime"]` |
 
 ### Option `graphqlSchemas`