feat(docs): adding haproxy configuration example

documentation/docs/install/getting_started.md

@@ -13,3 +13,4 @@ AdventureLog can be installed in a variety of ways. The following are the most c
 - [Nginx Proxy Manager](nginx_proxy_manager.md) 🛡
 - [Traefik](traefik.md) 🚀
 - [Caddy](caddy.md) 🔒
+- [HAProxy](haproxy.md)

documentation/docs/install/haproxy.md

@@ -0,0 +1,23 @@
+# Installation with Haproxy
+
+HAProxy is a free and open source software that provides a high availability load balancer and Proxy for TCP and HTTP-based applications.
+
+You need to make the frontend and the backend available in order to have your AdventureLog working properly.
+To do this, you will need to add 2 ACLs and 2 corresponding HAProxy backends in your haproxy configuration :
+- One for your regular Adventurelog domain that will direct the requests to the frontend.
+- One for the URLs that need to access the backend.
+
+Example :
+
+```
+acl is_adventurelog hdr_sub(Host) -i adventurelog
+acl is_adventurelog_backend path_beg /media/ or /admin/
+
+use_backend adventurelog_media if is_adventurelog is_adventurelog_backend
+use_backend adventurelog if is_adventurelog
+
+backend alog
+    server adventurelog 192.168.1.100:3000 check
+backend adventurelog_backend
+    server adventurelog_media 192.168.1.100:8000 check
+```