Docker Image php 7.0 FPM with gmp mysql gd iconv

Dockerfile

FROM php:7.0-fpm-stretch

RUN apt-get update && apt-get install -q -y ssmtp mailutils

RUN apt-get update && apt-get install -y \
        libfreetype6-dev \
        libjpeg62-turbo-dev \
        libpng-dev \
        libgmp-dev \
    && docker-php-ext-install -j$(nproc) iconv \
    && docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ \
    && docker-php-ext-install -j$(nproc) gd \
    && docker-php-ext-install mysqli \
    && docker-php-ext-install gmp

RUN rm -rf /var/lib/apt/lists/*
RUN echo "hostname=localhost.localdomain" > /etc/ssmtp/ssmtp.conf
RUN echo "root=root@example.com" >> /etc/ssmtp/ssmtp.conf
RUN echo "mailhub=maildev" >> /etc/ssmtp/ssmtp.conf

RUN echo "sendmail_path=sendmail -i -t" >> /usr/local/etc/php/conf.d/php-sendmail.ini

RUN echo "localhost localhost.localdomain" >> /etc/hosts