Added drone build

.drone.yml

@@ -10,17 +10,7 @@ steps:
   image: hseeberger/scala-sbt:11.0.2_2.12.8_1.2.8
   commands:
   - sbt test
-- name: dockerfile
+- name: docker:publish
   image: hseeberger/scala-sbt:11.0.2_2.12.8_1.2.8
   commands:
-  - sbt docker:stage
-- name: docker
-  image: plugins/docker
-  settings:
-    repo: https://registry.xeppaka.eu:443
-    tags: 1.0.0
-    dockerfile: target/docker/stage/Dockerfile
-    username:
-      from_secret: docker_username
-    password:
-      from_secret: docker_password
+  - sbt docker:publish