Update documentation from recent data tweaks?

[drewvolz]

From the "refactored" branch, I'm wondering if the README needs updating according to the recent data tweaks.

Merge branch 'refactored'

• refactored:
  run data editing on 2018 courses
  join times/locations into an "offerings" array
  rename "enroll" to "enrolled"
  remove departments array, since things like CH/BI are technically a distinct department from CHEM/BIO
  stringify crsid/clbid/groupid, since they're opaque identifiers

[hawkrives]

Yes

[drewvolz]

StoDevX/course-data-tools#5

• clbid/crsid/groupid are now string, not int
• departments is now department and no longer an array, and should not be split into multiple * departments
• enroll is now enrolled
• locations/times is now offerings – offerings: [{day: Fr, location: RNS 203, start: "11:00", end: "11:50"}] (times are in 24-hr format)

[hawkrives]

Offerings will be the tricky part, because it's nested. The others should be