Update Readme.md (chirag04#154)

Changed the installation steps to use `react-native install` rather than the old `rnpm`

Author: cainaleaouk

Readme.md

@@ -17,11 +17,9 @@ A react-native wrapper for handling in-app purchases.
 
 ### Add it to your project
 
-1. Make sure you have `rnpm` installed: `npm install rnpm -g`
+1.Install with react-native cli `react-native install react-native-in-app-utils`
 
-2. Install with rnpm: `rnpm install react-native-in-app-utils`
-
-3. Whenever you want to use it within React code now you just have to do: `var InAppUtils = require('NativeModules').InAppUtils;`
+2. Whenever you want to use it within React code now you just have to do: `var InAppUtils = require('NativeModules').InAppUtils;`
    or for ES6:
 
 ```