gitlab_runner/Dockerfile: Dockerfile to add self signet ssl certificate of gitlab

gitlab_runner/Dockerfile

+FROM gitlab/gitlab-runner:latest
+MAINTAINER Laurent Modolo
+
+RUN openssl s_client -connect gitlab.biologie.ens-lyon.fr:443 \
+  -showcerts </dev/null 2>/dev/null | \
+  openssl x509 -outform PEM | \
+  tee /usr/local/share/ca-certificates/gitlab.biologie.ens-lyon.fr.crt && \
+  update-ca-certificates
+