Merge pull request #30 from taion/update-docs

Clarify <ScrollContainer> docs

README.md

@@ -65,7 +65,7 @@ useScroll((prevRouterProps, { routes }) => {
 
 ### Scrolling elements other than `window`
 
-Use `<ScrollContainer>` to manage the scroll behavior of elements other than `window`. Each `<ScrollContainer>` must be given a unique `scrollKey`, and can be given an optional `shouldUpdateScroll` callback that behaves as above.
+Use `<ScrollContainer>` in components rendered by a router with the `useScroll` middleware to manage the scroll behavior of elements other than `window`. Each `<ScrollContainer>` must be given a unique `scrollKey`, and can be given an optional `shouldUpdateScroll` callback that behaves as above.
 
 ```jsx
 import { ScrollContainer } from 'react-router-scroll';