adds a section on creating custom transforms
adds a section on creating custom transforms

jkarsrud/guides,jackfranklin/guides,HeroicEric/guides,bmac/guides,nicobot/guides,davidpett/guides,ubuntuvim/guides,MarkMT/guides,bmac/guides,skaterdav85/guides,vikram7/guides,HeroicEric/guides,bmac/guides,boztek/guides,jkarsrud/guides,greyhwndz/guides,ubuntuvim/guides,MarkMT/guides,jkarsrud/guides,tleskin/guides,tleskin/guides,davidpett/guides,knownasilya/guides,skaterdav85/guides,skaterdav85/guides,jackfranklin/guides,HeroicEric/guides,nicobot/guides,knownasilya/guides,greyhwndz/guides,greyhwndz/guides,davidpett/guides,vikram7/guides,jkarsrud/guides,bmac/guides,ubuntuvim/guides,tleskin/guides,jackfranklin/guides,boztek/guides,knownasilya/guides,ubuntuvim/guides,nicobot/guides,davidpett/guides,boztek/guides,knownasilya/guides,skaterdav85/guides,MarkMT/guides,vikram7/guides,MarkMT/guides