Before installing Rails you should install Apache and MySQL. To install the Apache package, please refer to the section called “HTTPD - Apache2 Web Server”. For instructions on installing MySQL refer to the section called “MySQL”.

Once you have Apache and MySQL packages installed, you are ready to install Ruby on Rails package.

To install the Ruby base packages and Ruby on Rails, you can enter the following command in the terminal prompt:

sudo apt-get install rails

Modify the /etc/apache2/sites-available/default configuration file to setup your domains.

The first thing to change is the DocumentRoot directive:

DocumentRoot /path/to/rails/application/public

Next, change the <Directory "/path/to/rails/application/public"> directive:

<Directory "/path/to/rails/application/public">
        Options Indexes FollowSymLinks MultiViews ExecCGI
        AllowOverride All
        Order allow,deny
        allow from all
        AddHandler cgi-script .cgi
</Directory>

You should also enable the mod_rewrite module for Apache. To enable mod_rewrite module, please enter the following command in a terminal prompt:

sudo a2enmod rewrite

Finally you will need to change the ownership of the /path/to/rails/application/public and /path/to/rails/application/tmp directories to the user used to run the Apache process:

sudo chown -R www-data:www-data /path/to/rails/application/public
sudo chown -R www-data:www-data /path/to/rails/application/tmp

That's it! Now you have your Server ready for your Ruby on Rails applications.