migration.md

@@ -12,7 +12,13 @@ To update the version of your OC instance we do the next process:
 $ wget http://dl.opencellsoft.com/7.3.0/7.2.2_TO_7.3.0.sql
 ```
 
-  - Execute the script with `docker exec` as the `opencell` user (only this one has permissions for docker):
+  - Change to the `opencell` user (only this one has permissions for docker):
+
+```
+$ sudo su - opencell
+```
+  
+  - Execute the script with `docker exec`:
 
 ```
 $ docker exec -i postgres psql -U opencell opencell < 7.2.2_TO_7.3.0.sql