Add tip on docker deployment/self-host about mounting to top-level folders

[timothycarambat]

fixed chmod -R 777 /mnt/{whereve you are mounting using -v} Mintplex-Labs/anything-llm#1996

it is a very known bug. maybe can u put it on docs ?
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It's not a bug, it's just how linux works when you try mounting a userland application to a generic top-level folder 🤷

I guess its worth putting in docs for those that dont know since it seems to happen a lot!

Originally posted by @timothycarambat in #2294