templates/environment/server/inventory.erb
<%= params[:host] %> ansible_ssh_port=<%= params[:port] || 22 %>
[all]
<%= params[:host] %>
[application]
<%= params[:host] %>
[vm]
<%= params[:host] %>
[<%= params[:rails_env] %>]
<%= params[:host] %>
<% roles.each do |role| -%>
[<%= role %>]
<%= params[:host] %>
<% end %>