Added option loading example

README.md

@@ -91,6 +91,12 @@ Ash also takes care of loading the function pointers. Function pointers are spli
 let device: Device = instance.create_device(pdevice, &device_create_info)
     .unwrap();
 ```
+Additionally, every Vulkan extensions has to be loaded explicity. You can find all extensions under [ash::extensions](https://github.com/MaikKlein/ash/tree/master/src/extensions). You still have to tell Vulkan which instance or device extensions you want to load.
+```Rust
+use ash::extensions::Swapchain;
+let swapchain_loader = Swapchain::new(&instance, &device).expect("Unable to load swapchain");
+let swapchain = swapchain_loader.create_swapchain_khr(&swapchain_create_info).unwrap();
+```
 You don't have to pass an Instance or Device handle anymore, this is done implicitly for you.
 ```Rust
 // C