Add Contract for generating separate serialize/deserialize schemas (#335)

docs/3-generating.md

@@ -28,15 +28,14 @@ let my_schema = generator.into_root_schema_for::<MyStruct>();
 
 See the API documentation for more info on how to use those types for custom schema generation.
 
+### Serialize vs. Deserialize contract
+
+Of particular note is the `contract` setting, which controls whether the generated schemas should describe how types are serialized or how they're *de*serialized. By default, this is set to `Deserialize`. If you instead want your schema to describe the serialization behaviour, modify the `contract` field of `SchemaSettings` or use the `for_serialize()` helper method:
+
+{% include example.md name="serialize_contract" %}
+
 ## Schema from Example Value
 
 If you want a schema for a type that can't/doesn't implement `JsonSchema`, but does implement `serde::Serialize`, then you can generate a JSON schema from a value of that type using the [`schema_for_value!` macro](https://docs.rs/schemars/1.0.0--latest/schemars/macro.schema_for_value.html). However, this schema will generally be less precise than if the type implemented `JsonSchema` - particularly when it involves enums, since schemars will not make any assumptions about the structure of an enum based on a single variant.
 
-```rust
-let value = MyStruct { foo = 123 };
-let my_schema = schema_for_value!(value);
-```
-
-<!-- TODO:
-create and link to example
--->
+{% include example.md name="from_value" %}