Document "user" directive in example unicorn conf
examples/unicorn.conf: add a note about throttling signals
Sending the same signal faster than the receiver can process
means signals can get lost.
doc: emphasize the importance of stderr_path
While second nature to myself, stderr_path may be an
overlooked configuration parameter for some users. Also,
add a minimal sample configuration file that is shorter
and hopefully less intimidating to new users.
Add examples for nginx and unicorn
These should help make things easier for folks unfamiliar
with nginx setups.