Use PHP7 in Docker image

Add missing PHP extensions in Docker image

Dockerfile

@@ -1,10 +1,12 @@
-FROM php:5.6-apache
+FROM php:7.0-apache
 RUN apt-get update
 RUN curl -sL https://deb.nodesource.com/setup_6.x | bash -
-RUN apt-get install -y libicu-dev xz-utils git zlib1g-dev python nodejs
+RUN apt-get install -y libicu-dev xz-utils git zlib1g-dev python nodejs libgmp-dev gettext
 RUN docker-php-ext-install mbstring
 RUN docker-php-ext-install intl
 RUN docker-php-ext-install zip
+RUN docker-php-ext-install gmp
+RUN docker-php-ext-install gettext
 RUN a2enmod rewrite
 RUN curl -sS https://getcomposer.org/installer | php
 COPY resources/php.ini /usr/local/etc/php/