edit

container/conf/web/php7/conf.d/00_simplexml.ini

@@ -0,0 +1 @@
+extension=simplexml.so

src/docker/build/dev/php/v7/Dockerfile

@@ -4,7 +4,7 @@ MAINTAINER Rabin "https://github.com/shemic"
 
 ENV COMPOSER_HOME=/share/lib/php
 
-RUN apk add --no-cache --update curl php7-fpm php7-mysqli php7-pgsql php7-pdo_mysql php7-pdo_pgsql php7-gd php7-curl php7-mcrypt php7-json php7-zlib php7-xml php7-iconv php7-zip php7-phar php7-memcached php7-openssl php7-dom php7-redis php7-mbstring php7-session && curl -sS https://getcomposer.org/installer | php && mv composer.phar /usr/bin/composer && apk del curl && composer config -g repo.packagist composer https://packagist.phpcomposer.com
+RUN apk add --no-cache --update curl php7-fpm php7-mysqli php7-pgsql php7-pdo_mysql php7-pdo_pgsql php7-gd php7-curl php7-mcrypt php7-json php7-zlib php7-xml php7-iconv php7-zip php7-phar php7-memcached php7-openssl php7-dom php7-redis php7-mbstring php7-session php7-simplexml && curl -sS https://getcomposer.org/installer | php && mv composer.phar /usr/bin/composer && apk del curl && composer config -g repo.packagist composer https://packagist.phpcomposer.com
 
 COPY php.sh /entrypoint/php.sh