Quote strings in shell commands

Author: JacobSanford

Dockerfile

@@ -16,8 +16,8 @@ COPY ./scripts /scripts
 
 RUN apk --no-cache add php7 php7-fpm php7-json php7-zlib php7-xml php7-phar php7-iconv php7-mcrypt curl php7-curl php7-openssl php7-gd && \
   mkdir -p "$PHP_PID_DIR/" && \
-  chown ${NGINX_RUN_USER}:${NGINX_RUN_GROUP} "$PHP_PID_DIR/" && \
-  curl -sS https://getcomposer.org/installer | php -- --install-dir=${COMPOSER_PATH} --filename=composer && \
+  chown "$NGINX_RUN_USER":"$NGINX_RUN_GROUP" "$PHP_PID_DIR/" && \
+  curl -sS https://getcomposer.org/installer | php -- --install-dir="$COMPOSER_PATH" --filename=composer && \
   cp /conf/nginx/app.conf "$NGINX_APP_CONF_FILE" && \
   cp /conf/php/app-php.ini "$PHP_APP_INI_FILE" && \
   cp /conf/php/app-php-fpm.conf "$PHP_FPM_APP_CONF_FILE" && \