Add documentation to `RedisBackend`.
Add documentation to `RedisBackend`.

mvaled/sentry,JamesMura/sentry,imankulov/sentry,ifduyue/sentry,fotinakis/sentry,beeftornado/sentry,JamesMura/sentry,JamesMura/sentry,BuildingLink/sentry,BuildingLink/sentry,mitsuhiko/sentry,gencer/sentry,fotinakis/sentry,mvaled/sentry,zenefits/sentry,nicholasserra/sentry,JackDanger/sentry,looker/sentry,BuildingLink/sentry,imankulov/sentry,JackDanger/sentry,JackDanger/sentry,mvaled/sentry,JamesMura/sentry,zenefits/sentry,zenefits/sentry,mitsuhiko/sentry,mvaled/sentry,BuildingLink/sentry,looker/sentry,gencer/sentry,looker/sentry,JamesMura/sentry,fotinakis/sentry,daevaorn/sentry,imankulov/sentry,jean/sentry,jean/sentry,ifduyue/sentry,alexm92/sentry,jean/sentry,gencer/sentry,ifduyue/sentry,gencer/sentry,nicholasserra/sentry,BuildingLink/sentry,ifduyue/sentry,daevaorn/sentry,daevaorn/sentry,alexm92/sentry,mvaled/sentry,fotinakis/sentry,looker/sentry,zenefits/sentry,beeftornado/sentry,zenefits/sentry,gencer/sentry,jean/sentry,nicholasserra/sentry,jean/sentry,ifduyue/sentry,mvaled/sentry,alexm92/sentry,daevaorn/sentry,beeftornado/sentry,looker/sentry