Add Drone config

See https://github.com/superseriousbusiness/gotosocial/issues/65.

.drone.yml

@@ -0,0 +1,19 @@
+---
+kind: pipeline
+name: automated container publishing
+steps:
+  - name: publish image
+    image: plugins/docker
+    settings:
+      username:
+        from_secret: docker_reg_username
+      password:
+        from_secret: docker_reg_passwd
+      repo: decentral1se/gotosocial
+      tags: latest
+trigger:
+  branch:
+    - main
+  event:
+    exclude:
+      - pull_request

README.md

@@ -2,6 +2,8 @@
 
 ![patrons](https://img.shields.io/liberapay/patrons/dumpsterqueer.svg?logo=liberapay) ![receives](https://img.shields.io/liberapay/receives/dumpsterqueer.svg?logo=liberapay)
 
+[![Build Status](https://drone.autonomic.zone/api/badges/autonomic-cooperative/gotosocial/status.svg?ref=refs/heads/main)](https://drone.autonomic.zone/autonomic-cooperative/gotosocial)
+
 Federated social media software.
 
 ![Sloth logo made by Freepik from www.flaticon.com](./web/assets/sloth.png)