better build process explanation

Author: corevo

README.md

@@ -34,7 +34,7 @@ We are using [SideeX](http://sideex.org/) as a start point. The SideeX team was
 ```peru sync```  
 ```yarn``` or if using Node 10 ```yarn --ignore-engines```
 - Build the extension  
-```yarn build:ext``` or ```yarn build:ext:prod``` for production build
+```yarn build:ext:prod``` or ```yarn build:ext``` for faster development build (also includes beta features)
 - Install as developer on [Google Chrome](https://developer.chrome.com/extensions/getstarted#unpacked) or [Firefox](https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Temporary_Installation_in_Firefox)  
 
 Manifest located in `<Project Directory>/packages/selenium-ide/build/manifest.json`