CI: push tags to dockerhub (#3283)

Author: octomike

.circleci/config.yml

@@ -52,6 +52,7 @@ _build_main_image_py36: &build_main_image_py36
         --rm=false \
         --tag nipype/nipype:latest \
         --tag nipype/nipype:py36 \
+        $(test -z "${CIRCLE_TAG}" || echo --tag nipype/nipype:"${CIRCLE_TAG}") \
         --build-arg BUILD_DATE="$(date -u +"%Y-%m-%dT%H:%M:%SZ")" \
         --build-arg VCS_REF="$(git rev-parse --short HEAD)" \
         --build-arg VERSION="${CIRCLE_TAG}" /home/circleci/nipype
@@ -192,6 +193,7 @@ jobs:
             docker push nipype/nipype:base
             docker push nipype/nipype:latest
             docker push nipype/nipype:py36
+            test -z "${CIRCLE_TAG}" || docker push nipype/nipype:"${CIRCLE_TAG}"
       - run:
           name: Move pruned Dockerfile to /tmp/docker/cache directory
           command: |
@@ -353,6 +355,8 @@ workflows:
           filters:
             branches:
               only: master
+            tags:
+              only: /.*/
           requires:
             - test_pytest
       - deploy_pypi: