Add duneci/dune:git image

This is the current state of the Git master branch of the DUNE core modules.
The image needs to be rebuilt from time to time.

We use a staged build to make sure to only update the image if the tests for
the core modules pass.

Makefile

@@ -23,6 +23,12 @@ dune-fufem-stamp: dune-fufem/Dockerfile dune-2.4-stamp
 	docker build -t duneci/dune-fufem:2.4 dune-fufem
 	touch $@
 
+dune-git-stamp: base-9-stamp dune-git/Dockerfile
+	docker build -t duneci/dune:git-staging dune-git
+	docker run -i duneci/dune:git-staging sh -c "dunecontrol make build_tests && dunecontrol make test"
+	docker tag -f duneci/dune:git-staging duneci/dune:git
+	touch $@
+
 dune-latest-stamp: dune-2.4-stamp
 	docker tag -f duneci/dune:2.4 duneci/dune:latest
 	touch $@

dune-git/Dockerfile

+FROM duneci/base:9
+
+USER root
+WORKDIR /
+RUN apt-get install --no-install-recommends --yes libug-dev
+
+USER duneci
+WORKDIR /duneci
+RUN mkdir -p modules
+WORKDIR /duneci/modules
+RUN git clone https://gitlab.dune-project.org/core/dune-common.git
+RUN git clone https://gitlab.dune-project.org/core/dune-geometry.git
+RUN git clone https://gitlab.dune-project.org/core/dune-grid.git
+RUN git clone https://gitlab.dune-project.org/core/dune-istl.git
+RUN git clone https://gitlab.dune-project.org/core/dune-localfunctions.git
+RUN ./dune-common/bin/dunecontrol all
+
+USER root
+WORKDIR /
+RUN ln -s /duneci/modules/dune-common/bin/dunecontrol /usr/local/bin/
+
+USER duneci
+WORKDIR /duneci
+ENV DUNE_CONTROL_PATH=.:/duneci/modules