install PHP composer

Author: johnroyer

dev/docker/Dockerfile

@@ -18,13 +18,13 @@ RUN a2enmod rewrite && \
 RUN ( curl -sSLf https://github.com/mlocati/docker-php-extension-installer/releases/latest/download/install-php-extensions -o - || echo 'return 1' ) | sh -s \
        gd ldap pdo_mysql xdebug zip
 
+# Install composer
+COPY --from=composer:latest /usr/bin/composer /bin/composer
+
 ENV APACHE_DOCUMENT_ROOT /app/public
 WORKDIR /app
 
 RUN <<EOR
-# Install composer
-curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
-
 # Use the default production configuration and update it as required
 mv "$PHP_INI_DIR/php.ini-production" "$PHP_INI_DIR/php.ini"
 sed -i 's/memory_limit = 128M/memory_limit = 512M/g' "$PHP_INI_DIR/php.ini"