Revert "Remove docker build from pipeline (using dockerhub)"

This reverts commit 0583e45f1c.

.drone.yml

@@ -27,3 +27,36 @@ steps:
   # Upload coverage report
   - pip install codecov
   - codecov
+
+---
+kind: pipeline
+name: publish
+
+steps:
+- name: tag
+  image: alpine
+  commands:
+  - echo "$DRONE_COMMIT_SHA" > .tags
+  when:
+    event:
+      exclude:
+      - tag
+
+- name: tag-release
+  image: alpine
+  commands:
+  - echo "$DRONE_TAG,latest" > .tags
+  when:
+    event:
+    - tag
+
+- name: docker
+  image: plugins/docker
+  settings:
+    auto_tag: false
+    username:
+      from_secret: DOCKER_USERNAME
+    password:
+      from_secret: DOCKER_PASSWORD
+
+depends_on: [test]