updated docker docs

docs/hero_mdbook_docker.md

@@ -37,10 +37,16 @@ Note that you will need to adjust the local path of the git repo and the docker
   ```
   sudo docker exec -it herodocker bash
   ```
-- Set git globally with a safe directory
+- Git configuration
+  - Set git lobally with a safe directory
     ```
     git config --global --add safe.directory /root/code/git.ourworld.tf/tfgrid/info_tfgrid
     ```
+  - Set your name and email to be able to push changes
+    ```
+    git config --global user.email "you@example.com"
+    git config --global user.name "Your Name"
+    ```
 - You can now use Hero normally, e.g. with **projectinca**
   - With a URL:
     ```