[dist] Fix image builds in docker hub

It seems that docker hub assumes that the directory containing the
docker file is the build context.
If that's correct, this should fix our image build in docker hub.

src/api/Dockerfile.frontend-base

@@ -0,0 +1,29 @@
+FROM openbuildservice/base
+
+RUN /root/bin/docker-bootstrap.sh frontend
+
+# Install other requirements
+RUN npm install -g jshint
+
+ADD Gemfile /obs/src/api/Gemfile
+ADD Gemfile.lock /obs/src/api/Gemfile.lock
+RUN chown -R frontend /obs/src/api
+
+# Ensure there are ruby, gem and irb commands without ruby suffix
+RUN for i in ruby gem irb; do ln -s /usr/bin/$i.ruby2.5 /usr/local/bin/$i; done
+
+# Now do the rest as the user with the same ID as the user who
+# builds this container
+USER frontend
+WORKDIR /obs/src/api
+
+# Install our bundle
+# FIXME: Retrying bundler if it fails is a workaround for https://github.com/moby/moby/issues/783
+#        which seems to happen on openSUSE (< Tumbleweed 20171001)...
+RUN export NOKOGIRI_USE_SYSTEM_LIBRARIES=1; bundle install --jobs=3 --retry=3 || bundle install --jobs=3 --retry=3
+
+# Switch to root again so we don't block changing our frontend user id...
+USER root
+
+# Run our command
+CMD ["/bin/bash", "-l"]

src/api/docker-files/Dockerfile.frontend-base

@@ -0,0 +1 @@
+../Dockerfile.frontend-base