feat: Build docker image in CI

.drone.yml

@@ -0,0 +1,23 @@
+---
+kind: pipeline
+type: exec
+name: build
+
+platform:
+  os: linux
+  arch: arm64
+
+steps:
+- name: build
+  commands:
+    - docker build -t gcrkrause/mastodon-blocklist-deploy .
+- name: push
+  environment:
+    USERNAME:
+      from_secret: docker-hub-user
+    PASSWORD:
+      from_secret: docker-hub-pw
+  commands:
+    - docker login -u $USERNAME -p $PASSWORD
+    - docker push gcrkrause/mastodon-blocklist-deploy
+    - docker image prune -a -f