Document remaining combinators in Persist.hs
Document remaining combinators in Persist.hs

plow-technologies/persistent,yesodweb/persistent,erikd/persistent,bitemyapp/persistent,rdnetto/persistent,pseudonom/persistent,psibi/persistent,naushadh/persistent,rdnetto/persistent,gbwey/persistent,paul-rouse/persistent,gbwey/persistent,gbwey/persistent,pseudonom/persistent,creichert/persistent