add example nginx config

nginx.example/conf.d/gitea.conf

@@ -0,0 +1,36 @@
+server {
+    listen 80;
+    server_name git.example.com;
+    
+    location /.well-known/acme-challenge/ {
+        root /var/www/certbot;
+    }
+
+    location / {
+        return 301 https://$host$request_uri;
+    }
+}
+
+server {
+    listen 443 ssl http2;
+    server_name git.example.com;
+
+    ssl_certificate /etc/letsencrypt/live/git.example.com/fullchain.pem;
+    ssl_certificate_key /etc/letsencrypt/live/git.example.com/privkey.pem;
+    
+    ssl_protocols TLSv1.2 TLSv1.3;
+    ssl_ciphers HIGH:!aNULL:!MD5;
+    ssl_prefer_server_ciphers on;
+
+    client_max_body_size 512M;
+
+    location / {
+        proxy_pass http://127.0.0.1:3000;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header X-Forwarded-Host $host;
+        proxy_set_header X-Forwarded-Port $server_port;
+    }
+}