Add /epics directory for testing

Dockerfile

@@ -59,6 +59,10 @@ ENV USERNAME gitlab-ci
 RUN groupadd -r -g 100000 ${USERNAME} \
   && useradd --no-log-init -r -m -g ${USERNAME} -u 10043 ${USERNAME}
 
+# Create /epics directory in the image so that we can test
+# without mounting an external dir
+RUN mkdir /epics && chown ${USERNAME}:${USERNAME} /epics
+
 USER ${USERNAME}
 WORKDIR /home/${USERNAME}