Add a HOME to db migrate command in omnibus

Our calls to `bundle exec` in the omnibus install need to have a HOME set
because of an updated rb-readline that requires it.[1] This is related to
28345e92, where a HOME was added to the runit startup scripts for rails
and sidekiq. This is the only other `bundle exec` in the omnibus cookbook
and so it needs a HOME, too.

[1] ConnorAtherton/rb-readline#8

Signed-off-by: Robb Kidd <rkidd@chef.io>

omnibus/cookbooks/omnibus-supermarket/recipes/database.rb

@@ -80,6 +80,9 @@
 execute 'database schema' do
   command 'bundle exec rake db:migrate db:seed'
   cwd node['supermarket']['app_directory']
-  env 'RAILS_ENV' => 'production'
+  environment({
+    'RAILS_ENV' => 'production',
+    'HOME' => node['supermarket']['app_directory']
+  })
   user node['supermarket']['user']
 end