Add a logging facility

[mikldt]

When we start the app with bandshelld, we should log important events like errors, remote logins, and initial setup/authentication, to somwhere that they can read back, even if it just lasts until the next restart, this would let us go in and debug. Right now any output seems to go to the bit bucket.

Sinatra's built-in / plugin-based logging facilities aren't clear and probably deserve some research.

Something to think about: can we save the logs in non-volatile storage? How would we deal with running out of storage space?

[mikldt]

Note: it looks like the daemons gem can redirect STDOUT and STDERR to a file; this might be an approach worth considering.

http://daemons.rubyforge.org/Daemons.html#method-c-run