Add documentation to reflect `add_event_handler` (#129)

* Update applications docs

* Update events docs

* slight reword

* make requested changes

* split into two examples

docs/applications.md

@@ -45,10 +45,19 @@ You can use any of the following to add handled routes to the application:
 
 * `app.add_route(path, func, methods=["GET"])` - Add an HTTP route. The function may be either a coroutine or a regular function, with a signature like `func(request, **kwargs) -> response`.
 * `app.add_websocket_route(path, func)` - Add a websocket session route. The function must be a coroutine, with a signature like `func(session, **kwargs)`.
-* `app.add_graphql_route(path, schema, executor=None) - Add a GraphQL route.
+* `app.add_graphql_route(path, schema, executor=None)` - Add a GraphQL route.
 * `@app.route(path)` - Add an HTTP route, decorator style.
 * `@app.websocket_route(path)` - Add a WebSocket route, decorator style.
 
+### Adding event handlers to the application
+
+There are two ways to add event handlers:
+
+* `@app.on_event(event_type)` - Add an event, decorator style
+* `app.add_event_handler(event_type, func)` - Add an event through a function call.
+
+`event_type` must be specified as either `'startup'` or `'cleanup'`.
+
 ### Submounting other applications
 
 Submounting applications is a powerful way to include reusable ASGI applications.

docs/events.md

@@ -8,7 +8,7 @@ is shutting down.
 These event handlers can either be `async` coroutines, or regular syncronous
 functions.
 
-The event handlers are registered with a decorator syntax, like so:
+The event handlers can be registered with a decorator syntax, like so:
 
 ```python
 from starlette.applications import Starlette
@@ -23,6 +23,23 @@ async def open_database_connection_pool():
 @app.on_event('cleanup')
 async def close_database_connection_pool():
     ...
+```
+Or as a regular function call:
+
+```python
+from starlette.applications import Starlette
+
+
+app = Starlette()
+
+async def open_database_connection_pool():
+    ...
+
+async def close_database_connection_pool():
+    ...
+
+app.add_event_handler('startup', open_database_connection_pool)
+app.add_event_handler('cleanup', close_database_connection_pool)
 
 ```