Convert Apache proxy balancer config to Caddy

how do I convert this Apache config to Caddy?
Apache has balancer proxy to Ruby-based forum.
It serves static files, and for what is not found
is server by forum.

<VirtualHost *:80>

	DocumentRoot /var/www/forum/public
	<Directory />
		Options FollowSymLinks
		AllowOverride None
	<Directory /var/www/forum/public>
		Options Indexes FollowSymLinks MultiViews
		AllowOverride None
		Order allow,deny
		allow from all

	RewriteEngine On
	<Proxy balancer://thins>
		BalancerMember http://localhost:5000

        # Redirect forum posts
	RewriteRule ^/topics/(.*)/posts/(.*) /posts/$2 [L,R=301]
        Include /etc/apache2/forum-redirects.conf
        # included forum-redirects.conf file has many lines like these two lines:
        RewriteRule ^/topics/1$ /forums/1/topics/1 [L,R=301]
        RewriteRule ^/topics/2$ /forums/1/topics/2 [L,R=301]

	RewriteRule ^/.*$ balancer://thins%{REQUEST_URI} [P,QSA,L]
	ProxyPassReverse / balancer://thins/
	<Proxy *>
		Order allow,deny
		allow from all

	ErrorLog ${APACHE_LOG_DIR}/forum-error.log
	LogLevel warn
	CustomLog ${APACHE_LOG_DIR}/forum-access.log anoncommon