Added documentation step

.drone.yml

@@ -23,6 +23,11 @@ steps:
     image: boechat107/pgsanity
     commands:
       - pgsanity docker/backend/db/**/*.sql
+  - name: documentation
+    image: crystal-lang/crystal:latest-alpine
+    commands:
+      - cd docker/backend/
+      - crystal docs
   - name: build
     image: tmaier/docker-compose
     volumes:
@@ -34,6 +39,7 @@ steps:
     depends_on:
       - ameba
       - pgsanity
+      - documentation
 volumes:
   - name: dockersock
     host: