wording & command fixes [skip ci] 
wording & command fixes [skip ci] 

-- grammar
-- "Generally speaking" not helpful here. If there is a specific case where it's ok to run a migration while containers online, explain what that case is. Otherwise just leave it out.

-- `mongo MedBook` breaks on prod with `exception: connect failed`
==
UCSC-MedBook/MedBook_,UCSC-MedBook/MedBook_,UCSC-MedBook/MedBook_,UCSC-MedBook/MedBook_,UCSC-MedBook/MedBook_,UCSC-MedBook/MedBook_