Update examples.md

Author: tannerlinsley

docs/examples.md

@@ -6,3 +6,5 @@
   - This very basic example uses the `useField` hook to create a reusable `<InputField>` component that can be used inside of a form created by `useForm`
 - [Validation Example](https://codesandbox.io/s/react-form-demo-q9mgm)
   - This example demonstrates a variety of validation strategies possible with React Form
+- [Custom Select & Multi-Select Inputs](https://codesandbox.io/s/react-form-custom-select-multi-select-inputs-q5ixs)
+  - This example demonstrates how to build custom input fields, specifically a Select and Multi-Select input as examples.