Update Dockerfile

Rebase the image on the offical ubuntu image.
Add git, xz, libxml and gcc as dependencies
Change $PATH handling

Fixes eth-sri#15

Dockerfile

@@ -1,14 +1,8 @@
-FROM dlanguage/dmd
-LABEL "Version"="1.0"
+FROM ubuntu
 
 COPY . /opt/psi
 
-RUN apt -qq update && apt -qq install -y wget unzip
+RUN apt -qq update && apt -qq install -y wget unzip git xz-utils libxml2 gcc
 RUN cd /opt/psi && ./dependencies-release.sh && ./build-release.sh && mkdir bin && mv psi ./bin
 
-RUN echo "export PATH=$PATH:/opt/psi/bin" >> /root/.bashrc
-
-WORKDIR /root
-
-ENTRYPOINT ["bash"]
-
+ENV PATH=$PATH:/opt/psi/bin