Auto update to new versions.

[ejholmes]

Might be good to add something along the lines of https://github.com/inconshreveable/go-update, just to make it easier to make changes without having to tell everyone to update.

[benguillet]

This #20 fixes it, right?

[ejholmes]

Would still be kinda nice if it just updated itself periodically without having to supply the --update flag.

[phobologic]

I'd make that an option, which kind of goes against what you're saying in spirit. A lot of people get super touchy about things auto-updating on their system.