add note about hiredis install errors, thanks @taylorotwell
add note about hiredis install errors, thanks @taylorotwell

spjwebster/sixpack,llonchj/sixpack,seatgeek/sixpack,smokymountains/sixpack,seatgeek/sixpack,blackskad/sixpack,nickveenhof/sixpack,blackskad/sixpack,blackskad/sixpack,nickveenhof/sixpack,seatgeek/sixpack,vpuzzella/sixpack,smokymountains/sixpack,seatgeek/sixpack,blackskad/sixpack,llonchj/sixpack,spjwebster/sixpack,spjwebster/sixpack,vpuzzella/sixpack,llonchj/sixpack,smokymountains/sixpack,llonchj/sixpack,vpuzzella/sixpack,nickveenhof/sixpack,vpuzzella/sixpack