GG-15: Describe updating master in BEGINNERS.md
GG-15: Describe updating master in BEGINNERS.md

Merge branch 'git-fetch-beginners' into 'master'

added section about updating to snowdrift master

Beginners need a step where they know about keeping their
code up to date with the master snowdrift code.

See merge request !15

akegalj/snowdrift,chreekat/snowdrift,chreekat/snowdrift,akegalj/snowdrift,snowdriftcoop/snowdrift