auto travis release docker

.travis.yml

@@ -232,7 +232,15 @@ script:
     if [[ -n "$DOCKER_BUILD" ]]; then
       # push images - but only after tests pass within the container!
       echo "$DOCKER_PWD" | docker login -u $DOCKER_USR --password-stdin
-      $DCC run --rm sirf /bin/bash --login -c /devel/test.sh && $DCC push
+      $DCC run --rm sirf /bin/bash --login -c /devel/test.sh \
+        && $DCC push \
+        && if [[ -n "$TRAVIS_TAG" ]]; then ( set -ev
+             # tag release
+             docker tag ccppetmr/sirf:latest ccppetmr/sirf:"$TRAVIS_TAG"
+             docker tag ccppetmr/sirf:latest ccppetmr/sirf:release
+             docker push ccppetmr/sirf:"$TRAVIS_TAG"
+             docker push ccppetmr/sirf:release
+           ); fi
     else
       ./INSTALL/bin/gadgetron >& gadgetron.log&
       # print for debugging

docker/README.md

@@ -1 +1,34 @@
-See https://github.com/CCPPETMR/SIRF/wiki/SIRF-SuperBuild-on-Docker
+# SIRF on Ubuntu 16.04 on Docker
+
+Docker wrapper for CCP PET-MR SIRF.
+
+- [SIRF docker source]: https://github.com/CCPPETMR/SIRF-SuperBuild/tree/master/docker
+    + See also: [SIRF SuperBuild on Docker wiki]: https://github.com/CCPPETMR/SIRF/wiki/SIRF-SuperBuild-on-Docker
+- [Synergistic Image Reconstruction Framework (SIRF) project][SIRF]: https://github.com/CCPPETMR/SIRF
+    + [SIRF wiki]: https://github.com/CCPPETMR/SIRF/wiki
+- [Collaborative Computational Project in Positron Emission Tomography and Magnetic Resonance imaging (CCP PET-MR)][CCP PET-MR]: https://www.ccppetmr.ac.uk/
+
+[SIRF docker source]: https://github.com/CCPPETMR/SIRF-SuperBuild/tree/master/docker
+[SIRF SuperBuild on Docker wiki]: https://github.com/CCPPETMR/SIRF/wiki/SIRF-SuperBuild-on-Docker
+[SIRF]: https://github.com/CCPPETMR/SIRF
+[SIRF wiki]: https://github.com/CCPPETMR/SIRF/wiki
+[CCP PET-MR]: https://www.ccppetmr.ac.uk/
+
+## Tags
+
+The repository is hosted at [hub.docker.com][dockerhub-SIRF].
+To pull directly, use:
+
+```sh
+docker pull ccppetmr/sirf:<DOCKER_TAG>
+```
+
+| `<DOCKER_TAG>` | [SuperBuild] branch/tag |
+|:--- |:--- |
+| `release` | `<latest_tag>` |
+| `<tag>` | `<tag>` |
+| `latest` | `master` |
+| `devel` | `master` with `cmake -DDEVEL_BUILD=ON` |
+
+[dockerhub-SIRF]: https://hub.docker.com/r/ccppetmr/sirf/
+[SuperBuild]: https://github.com/CCPPETMR/SIRF-SuperBuild/