Help with Rails Application in Apache

I need help with getting a rails application working with
Apache.

I have the following virtual host configuration

ServerName concerto
DocumentRoot /usr/share/concerto/public

RackEnv production
AllowOverride all
Options -MultiViews

PassengerMinInstances 3

In the directory /usr/share/concerto, these are the directories

app config.ru Gemfile lib public test
bin db Gemfile.lock LICENSE Rakefile tmp
Capfile doc Gemfile-plugins log README.md tools
config Dockerfile Gemfile-reporting Procfile script vendor

In the directory /usr/share/concerto/public, these are the directories

assets favicon.ico favicon_inv.png favicon.png images robots.txt

When trying to access the IP address of the server in a browser, I get the
following message.

Forbidden
You don't have permission to access this resource.

What I think is happening is that somewhere in the Apache configuration, it is
not correctly using Passenger to locate the Ruby on Rails project.

Can anyone suggest what configuration to check so that the web server serves out
the Ruby on Rails project? Thanks.