diff --git a/README.md b/README.md
index 026f1a1d..a8c6de7a 100644
--- a/README.md
+++ b/README.md
@@ -66,3 +66,32 @@ Any changes made to files from a git repository will be commited and pushed back
 to the origin repository. Please note that HDM will not pull updates from the
 origin repository and is **not** able to resolve possible conflicts, so you might
 want to make sure that your repository is only edited by HDM.
+
+## :warning: Update to >= 1.0.0
+
+### Set rails secret
+
+Don't forget to set SECRET_KEY_BASE env var in docker run, docker-compose, systemd or hieradata.
+
+```
+openssl rand -hex 16
+9dea7603c008dec285e4b231602a00b2
+
+SECRET_KEY_BASE="9dea7603c008dec285e4b231602a00b2"
+
+
+docker run -it --rm -p 3000:3000 -e DEVELOP=1 -e SECRET_KEY_BASE=9dea7603c008dec285e4b231602a00b2 ghcr.io/betadots/hdm:development
+```
+
+See [`docker-compose.yaml`](docker-compose.yaml).
+
+
+### Update db file
+
+Move existing db/development.sqlite3 to db/production.sqlite3
+
+```bash
+docker exec -it <container_id> bash
+mv db/development.sqlite3 db/production.sqlite3
+bin/rails db:environment:set RAILS_ENV=production
+```
diff --git a/docker-compose.yaml b/docker-compose.yaml
index dc915d11..cf540fd8 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -6,6 +6,7 @@ services:
     container_name: hdm
     environment:
       - TZ=Europe/Berlin
+      - SECRET_KEY_BASE="a_l0ng_c0mpl3x_strinG" # f.e.: openssl rand -hex 16
       # whether to enable dev mode with fake puppetdb or not
       # - DEVELOP=1
     # volumes: