Install imagemagick

Dockerfile

@@ -1,6 +1,6 @@
 FROM debian:stable
 
-RUN apt-get -y update && apt-get -y install nginx php5-fpm php5-mysql php-apc supervisor python-pip mysql-client
+RUN apt-get -y update && apt-get -y install nginx php5-fpm php5-mysql php-apc supervisor python-pip mysql-client imagemagick
 RUN pip install supervisor-stdout
 
 RUN mkdir userdata