diff --git a/docker-compose.yml b/docker-compose.yml
index 75d17d3bc2d..79384cb612a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -19,7 +19,9 @@ x-op-app: &app
   environment:
     - "RAILS_CACHE_STORE=memcache"
     - "OPENPROJECT_CACHE__MEMCACHE__SERVER=cache:11211"
+    - "OPENPROJECT_RAILS__RELATIVE__URL__ROOT=${OPENPROJECT_RAILS__RELATIVE__URL__ROOT:-}"
     - "DATABASE_URL=postgres://postgres:p4ssw0rd@db/openproject"
+    - "USE_PUMA=true"
     # set to true to enable the email receiving feature. See ./docker/cron for more options
     - "IMAP_ENABLED=false"
   volumes:
@@ -55,6 +57,7 @@ services:
       - "8080:80"
     environment:
       - APP_HOST=web
+      - "OPENPROJECT_RAILS__RELATIVE__URL__ROOT=${OPENPROJECT_RAILS__RELATIVE__URL__ROOT:-}"
     depends_on:
       - web
     networks:
diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index 72604463e27..cbfa57e9c5d 100755
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -41,11 +41,25 @@ if [ "$(id -u)" = '0' ]; then
 	mkdir -p $APP_DATA_PATH/{files,git,svn}
 	chown -R $APP_USER:$APP_USER $APP_DATA_PATH /etc/apache2/sites-enabled/
 
+	# Clean up any dangling PID file
+	rm -f $APP_PATH/tmp/pids/*
+
 	# Clean up a dangling PID file of apache
 	if [ -e "$APACHE_PIDFILE" ]; then
 	  rm -f $APACHE_PIDFILE || true
 	fi
 
+	# Fix assets path if relative URL is used
+	relative_url_root_without_trailing_slash="$(echo $OPENPROJECT_RAILS__RELATIVE__URL__ROOT | sed 's:/*$::')"
+	if [ "$relative_url_root_without_trailing_slash" != "" ]; then
+		for file in $(egrep -lR "/assets/" "$APP_PATH/public"); do
+			# only the font paths in the CSSs need updating
+			sed -i "s|/assets/|${relative_url_root_without_trailing_slash}/assets/|g" $file
+			# the .gz is the one served by puma, so rebuild it
+			gzip --force --keep $file
+		done
+	fi
+
 	if [ ! -z "$ATTACHMENTS_STORAGE_PATH" ]; then
 		mkdir -p "$ATTACHMENTS_STORAGE_PATH"
 		chown -R "$APP_USER:$APP_USER" "$ATTACHMENTS_STORAGE_PATH"
diff --git a/docker/proxy.conf.erb b/docker/proxy.conf.erb
index bd534b193fe..437c4ba0087 100644
--- a/docker/proxy.conf.erb
+++ b/docker/proxy.conf.erb
@@ -5,8 +5,8 @@
   ProxyRequests off
   ProxyPreserveHost On
 
-  <Location />
-    ProxyPass http://<%= ENV.fetch("APP_HOST", "127.0.0.1") %>:8080/ retry=0
-    ProxyPassReverse http://<%= ENV.fetch("APP_HOST", "127.0.0.1") %>:8080/
+  <Location <%= ENV.fetch("OPENPROJECT_RAILS__RELATIVE__URL__ROOT", "").chomp("/") %>/>
+    ProxyPass http://<%= ENV.fetch("APP_HOST", "127.0.0.1") %>:8080<%= ENV.fetch("OPENPROJECT_RAILS__RELATIVE__URL__ROOT", "").chomp("/") %>/ retry=0
+    ProxyPassReverse http://<%= ENV.fetch("APP_HOST", "127.0.0.1") %>:8080<%= ENV.fetch("OPENPROJECT_RAILS__RELATIVE__URL__ROOT", "").chomp("/") %>/
   </Location>
 </VirtualHost>
diff --git a/docker/supervisord b/docker/supervisord
index 9adf4b3a9b8..b6d5cd8b4d2 100755
--- a/docker/supervisord
+++ b/docker/supervisord
@@ -110,13 +110,5 @@ fi
 echo "-----> Database setup finished."
 echo "       On first installation, the default admin credentials are login: admin, password: admin"
 
-if [ -n "$OPENPROJECT_RAILS__RELATIVE__URL__ROOT" ]; then
-	echo
-	echo "-----> Precompiling assets since RAILS_RELATIVE_URL_ROOT is set. This may take a minute."
-	RAILS_RELATIVE_URL_ROOT=$OPENPROJECT_RAILS__RELATIVE__URL__ROOT bash /app/docker/precompile-assets.sh
-	echo "-----> Asset precompilation finished."
-	echo
-fi
-
 echo "-----> Launching supervisord..."
 exec /usr/bin/supervisord -c $APP_PATH/docker/supervisord.conf -e ${SUPERVISORD_LOG_LEVEL}