A shift organizer website


Hello world.

i need a shift organizer website for bars.
i need a php script (website) that can organize employees into shifts.

the basic functions that i need is:
every bar can create an account and add his own employees,
the shifts are different for bar to bar (some have 4 employees in shift, some open earlier / close later, ect),
every employee set the times (in shifts) that ones available for work (for the following week) and the manager sets the shifts,
bonus if the the script as an alorithem that can set the employees by itself,

the most important function is that the shifts that the manager sets for the bar will be sets as shifts and not hours
for example:
the first shift start at 6pm
enforcement start at 10pm
last shift start at 11pm

will be displayed as: -opening shift- , -enforcement shift- ,‘closing shift’-

my English is not that amazing and i hope you guys can understand.
** this is a refferecne i have (but its not in english): http://www.shiftorganizer.com/%D7%9E%D7%A1%D7%9B%D7%99%D7%9D-%D7%A4%D7%A0%D7%99%D7%9E%D7%99%D7%99%D7%9D