Made FLARUM_PUBLIC_PATH a configurable variable

Dockerfile

@@ -18,7 +18,8 @@ ENV GID=991 \
     DEBUG=false \
     LOG_TO_STDOUT=false \
     GITHUB_TOKEN_AUTH=false \
-    FLARUM_PORT=8888
+    FLARUM_PORT=8888 \
+    FLARUM_PUBLIC_PATH=/public
 
 RUN apk add --no-progress --no-cache \
     nginx \

rootfs/etc/nginx/nginx.conf

@@ -56,7 +56,7 @@ http {
     listen <FLARUM_PORT>;
     charset utf-8;
 
-    root /flarum/app/public;
+    root /flarum/app<FLARUM_PUBLIC_PATH>;
     index index.php;
 
     client_max_body_size <UPLOAD_MAX_SIZE>;

rootfs/usr/local/bin/startup

@@ -13,6 +13,7 @@ fi
 
 # Set file config for nginx and php
 sed -i "s/<FLARUM_PORT>/${FLARUM_PORT}/g" /etc/nginx/nginx.conf
+sed -i "s/<FLARUM_PORT>/${FLARUM_PUBLIC_PATH}/g" /etc/nginx/nginx.conf
 sed -i "s/<UPLOAD_MAX_SIZE>/${UPLOAD_MAX_SIZE}/g" /etc/nginx/nginx.conf /etc/php7/php-fpm.conf
 sed -i "s/<PHP_MEMORY_LIMIT>/${PHP_MEMORY_LIMIT}/g" /etc/php7/php-fpm.conf
 sed -i "s/<OPCACHE_MEMORY_LIMIT>/${OPCACHE_MEMORY_LIMIT}/g" /etc/php7/conf.d/00_opcache.ini
@@ -59,7 +60,7 @@ if [ ! -e '/etc/nginx/conf.d/custom-vhost-flarum.conf' ]; then
 fi
 
 # if installation was performed before
-if [ -e '/flarum/app/public/assets/rev-manifest.json' ]; then
+if [ -e "/flarum/app${FLARUM_PUBLIC_PATH}/assets/rev-manifest.json" ]; then
   echo "[INFO] Flarum already installed, init app..."
 
   sed -i -e "s|<DEBUG>|${DEBUG}|g" \