add custom view that allows for datetime in the shift_events index

[kctrlv]

Resolves #114

The way the Administrate gem renders DateTime objects by default is as Dates.

source

I referenced the Administrate docs to auto-generate a custom view, and modified the partial on lines 59-63 to override that default behavior for DateTimes. The formatting can be altered on line 62 as desired.

[jcasimir]

It's pretty interesting how the generator puts comments in the template. I've never seen that done before, but have definitely encountered the scenario where I have a partial and I'm not sure where it's being used. Looks like good work!

[bjmllr]

Thank you!