add docs about yaml
add docs about yaml

pamil/Sylius,Arminek/Sylius,diimpp/Sylius,Sylius/Sylius,Zales0123/Sylius,SyliusBot/Sylius,antonioperic/Sylius,antonioperic/Sylius,SyliusBot/Sylius,pamil/Sylius,101medialab/Sylius,SyliusBot/Sylius,lchrusciel/Sylius,loic425/Sylius,Sylius/Sylius,loic425/Sylius,Arminek/Sylius,Sylius/Sylius,lchrusciel/Sylius,antonioperic/Sylius,Zales0123/Sylius,loic425/Sylius,Zales0123/Sylius,Arminek/Sylius,diimpp/Sylius,diimpp/Sylius,pamil/Sylius,lchrusciel/Sylius,101medialab/Sylius,101medialab/Sylius