Mention "boards" command on QuickStart page
Mention "boards" command on QuickStart page

mplewis/platformio,awong1900/platformio,TimJay/platformio,aphelps/platformio,aphelps/platformio,dkuku/platformio,bkudria/platformio,platformio/platformio-core,awong1900/platformio,jrobeson/platformio,jrobeson/platformio,TimJay/platformio,TimJay/platformio,awong1900/platformio,bkudria/platformio,eiginn/platformio,aphelps/platformio,mcanthony/platformio,TimJay/platformio,platformio/platformio,atyenoria/platformio,mseroczynski/platformio,jrobeson/platformio,platformio/platformio-core,jrobeson/platformio,TimJay/platformio,bkudria/platformio,bkudria/platformio,valeros/platformio,ZachMassia/platformio,aphelps/platformio