Merge pull request #12 from corneliusweig/krew-readme

Improve readme instructions around the `krew` installation method

README.md

@@ -44,11 +44,16 @@ Get all resources...
 Also see [Usage](doc/USAGE.md).
 
 ## Installation
+There are several ways to install `ketall`. The recommended installation method is via `krew`.
 
 ### Via krew
+Krew is a `kubectl` plugin manager. If you have not yet installed `krew`, get it at
+[https://github.com/GoogleContainerTools/krew](https://github.com/GoogleContainerTools/krew).
+Then installation is as simple as
 ```bash
 kubectl krew install get-all
 ```
+The plugin will be available as `kubectl get-all`, see [doc/USAGE](doc/USAGE.md) for further details.
 
 ### Binaries
 When using the binaries for installation, also have a look at [doc/USAGE](doc/USAGE.md).