Add the database cookbook

... for setting up the production and staging databases.
Add the roa_maxx::database recipe
Include database recipes in appropriate role recipes
Compile cookbooks with "berks vendor"
Add the chruby cookbook
Configure the Ruby version
Include chruby in appropriate recipes
Compile cookbooks with "berks vendor"
Add the nginx cookbook
Create the roa_maxx::nginx recipe
Include roa_maxx::nginx in appropriate recipes
Compile cookbooks with "berks vendor"