nginx runs an subdomain to a new app with an existing website - nginx

Question

My server already has an RoR app running on Nginx at port 80 , now I want to set the Gitlab in the same server,
Now, I have to access the Gitlab by myserver:1987/
If I want to a access the Gitlab by myserver/gitlab
How to achieve it ?
nginx.conf
http{
include /opt/nginx/sites-enabled/*;
}
...
server {
listen 80;
server_name localhost;
passenger_enabled on;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
index index.html index.htm;
root /home/poc/projects/zeus/public;
passenger_enabled on;
}
sites-enabled/gitlab.conf
# GITLAB
# Maintainer: #randx
# CHUNKED TRANSFER
# It is a known issue that Git-over-HTTP requires chunked transfer encoding [0] which is not
# supported by Nginx < 1.3.9 [1]. As a result, pushing a large object with Git (i.e. a single large file)
# can lead to a 411 error. In theory you can get around this by tweaking this configuration file and either
# - installing an old version of Nginx with the chunkin module [2] compiled in, or
# - using a newer version of Nginx.
#
# At the time of writing we do not know if either of these theoretical solutions works. As a workaround
# users can use Git over SSH to push large files.
#
# [0] https://git.kernel.org/cgit/git/git.git/tree/Documentation/technical/http-protocol.txt#n99
# [1] https://github.com/agentzh/chunkin-nginx-module#status
# [2] https://github.com/agentzh/chunkin-nginx-module
upstream gitlab {
server unix:/home/git/gitlab/tmp/sockets/gitlab.socket;
}
server {
listen *:1987; # e.g., listen 192.168.1.1:80; In most cases *:80 is a good idea
server_name dqa-test; # e.g., server_name source.example.com;
server_tokens off; # don't show the version number, a security best practice
root /home/git/gitlab/public;
# Increase this if you want to upload large attachments
# Or if you want to accept large git objects over http
client_max_body_size 5m;
# individual nginx logs for this gitlab vhost
access_log /opt/nginx/logs/gitlab_access.log;
error_log /opt/nginx/logs/gitlab_error.log;
location / {
# serve static files from defined root folder;.
# #gitlab is a named location for the upstream fallback, see below
try_files $uri $uri/index.html $uri.html #gitlab;
}
# if a file, which is not found in the root folder is requested,
# then the proxy pass the request to the upsteam (gitlab unicorn)
location #gitlab {
proxy_read_timeout 300; # Some requests take more than 30 seconds.
proxy_connect_timeout 300; # Some requests take more than 30 seconds.
proxy_redirect off;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://gitlab;
}
error_page 502 /502.html;
}