add docs-centralizer CI job

.drone.yml

@@ -29,6 +29,19 @@ steps:
         - tag
         - deployment
 
+  - name: push-to-docs
+    image: git.fsfe.org/fsfe-system-hackers/docs-centralizer:latest
+    environment:
+      REPO_NAME: reminder-mails
+      SSH_PRIVATE_KEY:
+        # This is an organisation secret, so you don't need to set it
+        from_secret: docs_bot_private_key
+    when:
+      branch:
+        - master
+      event:
+        - push
+
 node:
   cont1: plutex
 

README.md

@@ -6,6 +6,7 @@ SPDX-License-Identifier: CC-BY-SA-4.0
 
 # Reminder Mails
 
+[![in docs.fsfe.org](https://img.shields.io/badge/in%20docs.fsfe.org-OK-green)](https://docs.fsfe.org/repodocs/reminder-mails/00_README)
 [![Build Status](https://drone.fsfe.org/api/badges/fsfe-system-hackers/reminder-mails/status.svg)](https://drone.fsfe.org/fsfe-system-hackers/reminder-mails)
 [![REUSE status](https://api.reuse.software/badge/git.fsfe.org/fsfe-system-hackers/reminder-mails)](https://api.reuse.software/info/git.fsfe.org/fsfe-system-hackers/reminder-mails)