Dockerfile
FROM php:7.0-cli-alpine
ENV PHPIZE_DEPS \
autoconf \
dpkg \
dpkg-dev \
file \
g++ \
gcc \
libc-dev \
make \
pkgconf \
re2c
USER root
RUN apk update \
&& apk --update add --virtual \
build-dependencies \
freetype-dev \
libjpeg-turbo-dev \
libpng-dev \
$PHPIZE_DEPS \
&& apk add \
freetype \
libjpeg-turbo \
libpng \
&& pecl install xdebug-2.5.0 \
&& docker-php-ext-enable xdebug \
&& docker-php-ext-configure gd \
--with-freetype \
--with-jpeg \
&& docker-php-ext-install \
gd \
&& curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
USER www-data