Override the rails restart command

Previously we always overrode this using the Stack Settings custom json.
As of opsworks chef 11.10, this attribute is declared as "normal"
instead of as "default", so the stack settings will not be used.

This changes our stacks to always use the restart command. It's
something we've used on every stack we've made, and is a generally
better default.
Merge pull request #18 from freerunningtech/rails_restart_command

Override the rails restart command