use entrypoint to shorten command

Dockerfile

@@ -1,13 +1,17 @@
-FROM ubuntu:14.04
+FROM ubuntu:18.04
 
 RUN \
   apt-get update; \
   apt-get install -y build-essential
 
+RUN \
+  apt-get update; \
+  apt-get install -y libgd-dev libzzip-dev libopencv-highgui-dev
+
 RUN \
   cd tmp; \
   apt-get update; \
-  apt-get install -y cmake3 wget; \
+  apt-get install -y cmake wget; \
   wget https://github.com/robotology/yarp/archive/v2.3.72.tar.gz; \
   tar xzvf v2.3.72.tar.gz; \
   mkdir yarp; \
@@ -15,10 +19,6 @@ RUN \
   cmake -DSKIP_ACE=TRUE ../yarp-*; \
   make 
 
-RUN \
-  apt-get update; \
-  apt-get install -y libgd2-noxpm-dev libzzip-dev
-
 COPY . /makesweet/
 
 RUN \
@@ -33,3 +33,5 @@ RUN \
   echo "cd /share" >> /reanimator; \
   echo "/makesweet/build/bin/reanimator \"\$@\"" >> /reanimator; \
   chmod u+x /reanimator
+
+ENTRYPOINT ["/reanimator"]

README.md

@@ -5,13 +5,13 @@ Input
 
 ![frog](https://user-images.githubusercontent.com/118367/39386221-9780dec0-4a41-11e8-827d-ec30fea33269.jpg)
 
-Calculations
-------------
+Running makesweet
+-----------------
 
 ```
-docker run -v $PWD:/share paulfitz/makesweet /reanimator \
+docker run -v $PWD:/share paulfitz/makesweet \
   --zip templates/billboard-cityscape.zip \
-  --in templates/frog.jpg \
+  --in images/frog.jpg \
   --gif animation.gif
 ```