Adding documentation for programmatically submitting a Form in React-Native. Fixes #625

Author: davidkpiano

docs/api/actions.md

@@ -395,7 +395,7 @@ If the promise fails, the action will:
 - set `.submitFailed` property of form for `model` to `true`
 - set `.errors` property of form for `model` to the response
 
-If a promise is not provided, e.g.: `actions.submit('user')`, then dispatching the action will trigger a `<Form>` with the specified `model` to submit itself.
+If a promise is not provided, e.g.: `actions.submit('user')`, then dispatching the action will trigger a `<Form>` with the specified `model` to call its `onSubmit` handler.
 
 ### Arguments
 - `model` _(String | Function)_: the model to be submitted

docs/guides/react-native.md

@@ -50,13 +50,27 @@ The use of `updateOn="blur"` will work as expected for the controls, and is set
 
 By default, the `<Form>` component is rendered as a `<View>`. It handles validity as expected, as well as partial models for child `<Control>` components, but it does not have an `onSubmit` mechanism.
 
-```js
+```jsx
 import { Form, Control } from 'react-redux-form/native';
 
 // render...
-<Form model="user">
+<Form model="user" onSubmit={/* ... */}>
+  <Control.TextInput model=".firstName" />
+  <Control.TextInput model=".lastName" />
+</Form>
+```
+
+To submit a React Native form programmatically:
+
+1. Ensure that the `<Form model="foo">` component has an `onSubmit={(values) => ...}` callback.
+2. Dispatch a submit action for the form's model (and no other arguments): `dispatch(actions.submit('foo'))`
+
+```jsx
+<Form model="user" onSubmit={(vals) => console.log(vals)}>
   <Control.TextInput model=".firstName" />
   <Control.TextInput model=".lastName" />
+
+  <Button onPress={() => dispatch(actions.submit('user'))} />
 </Form>
 ```