Add explanation about @platformio, how does it work

Author: ivankravets

README.md

@@ -50,7 +50,7 @@ python get.py
 
 ### Using PlatformIO
 
-[PlatformIO](http://platformio.org) is a cross-platform code-builder and library manager for embedded development with no external dependencies and support for Espressif platform. Works on the popular host OS: Mac OS X, Windows, Linux 32/64, Linux ARM (like Raspberry Pi, BeagleBone, CubieBoard).
+[PlatformIO](http://platformio.org) is a cross-platform code-builder and library manager for embedded development with no external dependencies and support for Espressif platform. Works on the popular host OS: Mac OS X, Windows, Linux 32/64, Linux ARM (like Raspberry Pi, BeagleBone, CubieBoard). More details in documentation [What is PlatformIO? How does it work?](http://docs.platformio.org/en/latest/faq.html#general).
 
 - Install [PlatformIO](http://platformio.org)
 - Initialise new project