fix: iconv incomplete in alpine docker

Dockerfile

@@ -1,10 +1,9 @@
 FROM alpine
-LABEL version="1.2" \
-      maintainer="dnomd343" \
-      description="echo client IP details"
+LABEL maintainer="dnomd343"
 COPY . /var/www/echoIP
 ADD ./conf/docker/init.sh /
-RUN apk --update add --no-cache nginx curl nodejs php7 php7-fpm php7-json php7-iconv php7-sqlite3 php7-openssl php7-mbstring && \
+ENV LD_PRELOAD /usr/lib/preloadable_libiconv.so php
+RUN apk --update add --no-cache nginx curl nodejs php7 php7-fpm php7-json php7-iconv php7-sqlite3 php7-openssl php7-mbstring gnu-libiconv && \
     mkdir -p /run/nginx && touch /run/nginx/nginx.pid && \
     cp /var/www/echoIP/conf/docker/ip.conf /etc/nginx/echoip.conf && \
     cp -f /var/www/echoIP/conf/docker/nginx.conf /etc/nginx/nginx.conf && \