Update 05.md (epicweb-dev#96)

Changes "responsible with" to "responsible for" because "responsible with" doesn't make sense there.

src/exercise/05.md

@@ -7,7 +7,7 @@ of these need to work directly with the DOM. Remember that when you do:
 `<div>hi</div>` that's actually syntactic sugar for a `React.createElement` so
 you don't actually have access to DOM nodes in your render method. In fact, DOM
 nodes aren't created at all until the `ReactDOM.render` method is called. Your
-component's render method is really just responsible with creating and returning
+component's render method is really just responsible for creating and returning
 React Elements and has nothing to do with the DOM in particular.
 
 So to get access to the DOM, you need to ask React to give you access to a