grammar

README.md

@@ -59,7 +59,7 @@ different virtual environments, and your problem is solved.
 Once again, each language has a different implementation. Python has
 [`virtualenv`](http://www.virtualenv.org/), Ruby has
 [`bundler`](http://gembundler.com/), and Node's virtual environment support
-is built into [`npm`](https://npmjs.org/), it's library management tool.
+is built into [`npm`](https://npmjs.org/), its library management tool.
 For each language, decide if you want to use a virtual environment, or if you
 want to install all the language dependencies globally (and risk conflicts).
 I suggest you start with installing things globally until and unless things