Add support for gmp & ffmpeg & svg

Dockerfile

@@ -53,6 +53,19 @@ RUN apt-get update && apt-get install -y \
 
 COPY supervisord.conf /etc/supervisord.conf
 
+##
+## GMP Support (for bookmark extension)
+##
+RUN apt-get update && apt-get install -y libgmp3-dev \
+ && docker-php-ext-install gmp
+
+##
+## SVG & Thumbnail support
+##
+RUN apt-get update && apt-get install -y \
+    libmagickcore-6.q16-6-extra ffmpeg \
+  && rm -rf /var/lib/apt/lists/* \
+
 ENV NEXTCLOUD_UPDATE=1
 
 CMD ["/usr/bin/supervisord", "-c", "/etc/supervisord.conf"]