Merge pull request digitalocean#139 from digitalocean/readme-go-get

README: add installation instructions

Author: mdlayher

README.md

@@ -7,6 +7,15 @@ instances.  Apache 2.0 Licensed.
 Feel free to join us in [`#go-qemu` on freenode](https://webchat.freenode.net/)
 if you'd like to discuss the project.
 
+Installation
+------------
+
+Use `go get` to retrieve all of the packages in `go-qemu`:
+
+```shell
+$ go get github.com/digitalocean/go-qemu/...
+```
+
 Overview
 --------