updated background color integration by adding a class against inline style

[lcrpt]

• I added some errors when i was trying to add a background color so i made some changes and i think this update will allow a better flexibility.
• the regex was return an array and not a css property
• It's better to call a css class than an inline css rule in our modules or controllers.
• also updated readme with this little update.
• updated readme ````html to ```html