Update Dockerfile.fpm

contrib/docker/Dockerfile.fpm

@@ -4,7 +4,7 @@ ARG COMPOSER_VERSION="1.8.5"
 ARG COMPOSER_CHECKSUM="4e4c1cd74b54a26618699f3190e6f5fc63bb308b13fa660f71f2a2df047c0e17"
 
 RUN apt-get update \
- && apt-get install -y --no-install-recommends git \
+ && apt-get install -y --no-install-recommends git gosu \
       optipng pngquant jpegoptim gifsicle libpq-dev libsqlite3-dev locales zip unzip libzip-dev \
       libfreetype6 libjpeg62-turbo libpng16-16 libxpm4 libvpx4 libmagickwand-6.q16-3 \
       libfreetype6-dev libjpeg62-turbo-dev libpng-dev libxpm-dev libvpx-dev libmagickwand-dev \