Try a promotion build to DockerHub.

.drone.yml

@@ -2,6 +2,11 @@ kind: pipeline
 type: kubernetes
 name: back-end
 
+# This pipeline tests the back-end using the integration tests.
+
+trigger:
+  event: [ push, pull_request ]
+
 workspace:
   path: /drone/src
 
@@ -27,6 +32,11 @@ kind: pipeline
 type: kubernetes
 name: front-end
 
+# This pipeline tests the front-end by running it through a TypeScript compiler.
+
+trigger:
+  event: [ push, pull_request ]
+
 workspace:
   path: /drone/src
 
@@ -41,3 +51,31 @@ steps:
   image: node
   commands:
   - cd /drone/src/client && ./node_modules/.bin/tsc; cd ..
+
+---
+kind: pipeline
+type: kubernetes
+name: dockerhub
+
+# This pipeline builds the docker container and publishes it
+# to DockerHub. The promotion target is "dockerhub".
+
+trigger:
+  event: [ promote ]
+
+steps:
+- name: prepare
+  image: alpine/git
+  commands:
+    - "echo \"dev-$(git rev-parse HEAD),latest\" > .tags"
+
+- name: publish
+  image: plugins/docker
+  settings:
+    repo: sandervocke/mudbase
+    username:
+      from_secret: docker_username
+    password:
+      from_secret: docker_password
+    dockerfile: deploy/Dockerfile
+