Add possibility to change default vhost port

[songsfromthewood]

Hello!

Thank for this repo. What do you think about possibility to change default vhost port using ENV variable?
Here is example with NGINX_VHOST_PORT`

`
diff --git a/templates/vhost.conf.tmpl b/templates/vhost.conf.tmpl
index a290042..cb3a3a7 100644
--- a/templates/vhost.conf.tmpl
+++ b/templates/vhost.conf.tmpl
@@ -1,7 +1,7 @@
include upstream.conf;

server {
- listen 80 default_server{{- if getenv "NGINX_HTTP2" }} http2{{- end }};
+ listen {{ getenv "NGINX_VHOST_PORT" "80" }} default_server{{- if getenv "NGINX_HTTP2" }} http2{{- end }};
server_name {{ getenv "NGINX_SERVER_NAME" "default" }};

 root {{ getenv "NGINX_SERVER_ROOT" "/var/www/html" }};

`

[csandanov]

I don't mind

[songsfromthewood]

Thanks for merging. Glad to improve this very useful and convenient docker image.
Sometimes default port should be different from default 80, so I'm sure this will be helpful for other people.
I made small inaccuracy in README.md, left spaces between var name and quotas:

NGINX_VHOST_PORT

Should be NGINX_VHOST_PORT instead.
I see my pull request is already closed, so please remove spaces when you'll have time.
Thanks in advance.

[csandanov]

changed it to NGINX_SERVER_PORT as more fitting, not NGINX_PORT because of the conflict with legacy kubernetes env vars

[songsfromthewood]

Got it.
Thanks for notifying me.

In one project I'm working on, I needed to set up port 81 for nginx. Therefore, I had to create a repository with the ability to change the port and a separate docker repository for the image.
Now I can use this image again and it saves time and efforts.
Thanks once again.