Ability to monitor a commute

[KyleBanks]

Would be nice to be able to monitor a commute, and optionally write the output to a file. By default, monitor would poll every minute, and the user could supply their own interval (in minutes).

Ex:

commuter monitor --from home --to work

Would print the commute time to stdout every minute.

commuter monitor --from home --to work --interval 5 --out file.txt

Would write the commute every five minutes to file.txt.