Nginx serving Gitlab and other projects

Hi,

i’m pretty new in server infrastructure and i have recently installed on a vps Gitlab with the Omnibus package on Ubuntu server 14.04.
Installation was fine and i can now access my Gitlab at my_vps.com/

But i also would like my Nginx server to manage my ruby projects and i don’t know how to do it…
I read about Nginx and its own embeded server so i edit the /etc/gitlab/gitlab.rb like this :

unicorn['enable'] = false
web_server['external_users'] = ['www-data']
nginx['enable'] = false
ci_nginx['enable'] = false

and after sudo gitlab-ctl reconfigure

I also configured my nginx.conf like this :

user www-data;
worker_processes 4;
pid /run/nginx.pid;

events {
    worker_connections 768;
}

http {
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
    ssl_prefer_server_ciphers on;

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    gzip on;
    gzip_disable "msie6";

    passenger_root /usr/lib/ruby/vendor_ruby/phusion_passenger/locations.ini;
    passenger_ruby /usr/bin/passenger_free_ruby;

    # test app conf
    server {
        listen 80 default_server;
        listen [::]:80 default_server;

        passenger_enabled on;
        passenger_ruby /home/dev/.rvm/gems/ruby-1.9.3-p551/wrappers/ruby;
        root /var/www/test_rails_app/public;

        index index.html index.htm index.nginx-debian.html;

        server_name my_vps.com;

        location /test-app {
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
                try_files $uri $uri/ =404;
        }
    }

    server {
        listen *:80;
        server_name my_vps.com;
        server_tokens off;
        root /opt/gitlab/embedded/service/gitlab-rails/public;

        client_max_body_size 250m;

        access_log  /var/log/gitlab/nginx/gitlab_access.log;
        error_log   /var/log/gitlab/nginx/gitlab_error.log;

        # Ensure Passenger uses the bundled Ruby version
        passenger_ruby /opt/gitlab/embedded/bin/ruby;

        # Correct the $PATH variable to included packaged executables
        passenger_env_var PATH "/opt/gitlab/bin:/opt/gitlab/embedded/bin:/usr/local/bin:/usr/bin:/bin";

        # Make sure Passenger runs as the correct user and group to
        # prevent permission issues
        passenger_user git;
        passenger_group git;

        # Enable Passenger & keep at least one instance running at all times
        passenger_enabled on;
        passenger_min_instances 1;

        error_page 502 /502.html;

        location /gitlab {
          try_files $uri $uri/index.html $uri.html @gitlab;
        }
} 

I can access Gitlab at my_vps.com/ but not my ruby app at my_vps.com/test-app

Can I have some help please ?