Add drone workflow

.drone.yml

@@ -0,0 +1,27 @@
+---
+kind: pipeline
+type: docker
+name: build
+
+steps:
+  - name: "Build Image"
+    image: "plugins/docker:20.14.4"
+    environment:
+      DOCKER_BUILDKIT: 1
+    settings:
+      registry: git.rabbithole.cyou
+      repo: git.rabbithole.cyou/paravielfalt/mastodon
+      config:
+        from_secret: docker_hub_credentials_dockerconfig
+      username:
+        from_secret: gitea_docker_registry_username
+      password:
+        from_secret: gitea_docker_registry_password
+      tags:
+        - "${DRONE_TAG}"
+      force_tag: true
+      dockerfile: Dockerfile
+    depends_on: ["Replace version tag"]
+
+trigger:
+  event: [tag]