doesn't try to display author if nil

This simple issue was responsible for a couple of 500 Internal
Server Error "We're sorry, but something went wrong"s in
deployment.
Heroku configuration gem (and, no .DS_Store)

Heroku says, "Add 'rails_12factor' gem to your Gemfile to skip
plugin injection." Okay.
query optimizing

This commit assisted greatly by the lovely Bullet gem.
entry must have description if no content
using a hardcoded secret token in development considered harmful

Thanks to
http://daniel.fone.net.nz/blog/2013/05/20/a-better-way-to-manage-the-rails-secret-token/
cosmetics

* fixed navbar (in more ways than one??)
* proper containers
* tweaks to forms
load entries if necessary on show page, too
cosmetics (form tweak, custom time)