Add documentation of API

README.md

@@ -13,6 +13,8 @@ imperial_doc_materials.init_app(app)
 imperial_doc_materials.set_redirect_url('auth.login')
 ```
 
+The ```set_redirect_url()``` method should take the route name of your login page.
+
 ## Using the Materials API in a Flask route
 
 Again, there are examples of this in the template. You must use the ```@using_materials``` decorator before the route function definition. This will give you access to a ```Materials``` client object which you can use to make requests.