Build and deploy manual in CI

.ci/known_hosts

@@ -0,0 +1 @@
+sallie.librepush.net,79.143.178.141 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBHPJu+9XaDuDQA8jVdD++BSkazgVUt1c22oa+FoWiqWVWAVu33+Jh3Evc4s3HK6jMMuOIVs8AVnGAUY5eaqmJik=

.drone.yml

@@ -23,3 +23,19 @@ steps:
       - ./testsuite/.venv/bin/pip install -e testsuite
       - cd testsuite && ./.venv/bin/green
 
+  - name: deploy manual
+    image: rust:1.53.0-slim
+    when:
+      branch:
+        - develop
+    environment:
+      DEPLOY_SSH_KEY:
+        from_secret: DEPLOY_SSH_KEY
+    commands: # warning! Doesn't seem to like hashed known_hosts...
+      - cargo install mdbook
+      - cd docs
+      - mdbook build
+      - echo "$DEPLOY_SSH_KEY" > /tmp/rsync_key
+      - chmod u=rw,go= /tmp/rsync_key
+      - rsync -e 'ssh -i /tmp/rsync_key -o "UserKnownHostsFile .ci/known_hosts"' -vaz --delete ./docs/book space_docs_librepush_net@sallie.librepush.net:./public/yama
+      - rm /tmp/rsync_key