Updating README

README.md

@@ -283,6 +283,49 @@ axios.get('/user/12345')
 });
 ```
 
+## Config Defaults
+
+You can specify config defaults that will be applied to every request.
+
+### Global axios defaults
+
+```js
+axios.defaults.baseURL = 'https://api.example.com';
+axios.defaults.headers.common['Authorization'] = AUTH_TOKEN;
+axios.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded';
+```
+
+### Custom instance defaults
+
+```js
+// Set config defaults when creating the instance
+var instance = axios.create({
+  baseURL: 'https://api.example.com'
+});
+
+// Alter defaults after instace has been created
+instance.defaults.headers.common['Authorization'] = AUTH_TOKEN;
+```
+
+### Config order of precedence
+
+Config will be merged with an order of precedence. The order is library defaults found in `lib/defaults.js`, then `defaults` property of the instance, and finally `config` argument for the request. The latter will take precedence over the former. Here's an example.
+
+```js
+// Create an instance using the config defaults provided by the library
+// At this point the timeout config value is `0` as is the default for the library
+var instance = axios.create();
+
+// Override timeout default for the library
+// Now all requests will wait 2.5 seconds before timing out
+instance.defaults.timeout = 2500;
+
+// Override timeout for this request as it's known to take a long time
+instance.get('/longRequest', {
+  timeout: 5000
+}); 
+```
+
 ## Interceptors
 
 You can intercept requests or responses before they are handled by `then` or `catch`.