Restricting build to 'push' event only. Adding git commit SHA as tag.

.drone.yml

@@ -17,6 +17,11 @@ steps:
 #      - 'bin/console lint:yaml'
   - name: docker-build
     image: plugins/docker
+    when:
+#      branch:
+#        - master
+      event:
+        - push
     settings:
       username:
         from_secret: docker_username
@@ -24,4 +29,6 @@ steps:
         from_secret: docker_token
       repo:
         from_secret: docker_repo
-      tags: latest
+      tags:
+        - latest
+        - ${DRONE_COMMIT_SHA:0:10}