Add additional instructions for django migrations

[grantfitzsimmons]

Fixes #3626

Is this explanation satisfactory?

[maxpatiiuk]

1. Small clarification: It's not that root is required, but that user with more permissions is required (my master user has all permissions, so I had no issues with this - of course that is not suitable for production). Worth clarifying or not worth the complexity?
2. When you modify docker compose, I believe you have to rebuild for changes to env variables to take effect - not sure. Could you try changing the MASTER_NAME and see if changes apply after restarting without rebuild?

[grantfitzsimmons]

• Small clarification: It's not that root is required, but that user with more permissions is required (my master user has all permissions, so I had no issues with this - of course that is not suitable for production). Worth clarifying or not worth the complexity?

I understood this before writing, but I was worried it would add too much complexity to explain this.

When you modify docker compose, I believe you have to rebuild for changes to env variables to take effect - not sure. Could you try changing the MASTER_NAME and see if changes apply after restarting without rebuild?

I can try this at a later date. I need to catch up on 3 weeks of messages 😉