Add drone integration

.drone.yml

@@ -0,0 +1,22 @@
+kind: pipeline
+type: docker
+name: default
+
+steps:
+  - name: publish
+    image: plugins/docker
+    settings:
+      auto_tag: true
+      registry:
+        from_secret: docker_registry
+      repo:
+        from_secret: docker_repo
+      username:
+        from_secret: docker_username
+      password:
+        from_secret: docker_password
+    when:
+      event:
+        - push
+        - tag
+      branch: master