Move the Dockerfile for the agent in a proper location

backend_agent/Dockerfile → utils/agent_container/Dockerfile

@@ -1,14 +1,15 @@
+# Download the sources of the agent from github and build the container from it.
+
 FROM centos
 
 RUN \
     yum -y update && \
     yum -y install epel-release && \
-    yum -y install docker python-pip gcc python-devel && \
+    yum -y install docker python-pip gcc python-devel git && \
     pip install pytidylib docutils rpyc cgroup-utils pyyaml
 
 # temp workaround for Docker 1.7 (TODO: revert me!)
 RUN \
-    yum -y install git && \
     git clone https://github.com/GuillaumeDerval/docker-py.git /docker-py && \
     cd /docker-py && \
     pip install . && \
@@ -18,8 +19,13 @@ RUN \
 VOLUME /agent_volume
 VOLUME /sys/fs/cgroup
 
-ADD common /agent/common
-ADD backend_agent /agent/backend_agent
+RUN \
+    mkdir /agent && \
+    git clone https://github.com/UCL-INGI/INGInious.git /INGInious && \
+    cp -r /INGInious/common /agent/common && \
+    cp -r /INGInious/backend_agent /agent/backend_agent && \
+    rm -rf /INGInious
+
 WORKDIR /agent
 CMD ["/agent/backend_agent/start_container_agent.py"]