users.conf not syncing after first setup

[quiquelhappy]

Hello,
I'd like to modify my users.conf after the container is created. It seems like the way it's currently setup, the container is making a copy upon setup and never reads the file again. This is the setup I'm using:

docker run 
      -v C:\Users\happy\Documents\purecore-containers\users.conf:/etc/sftp/users.conf:ro 
      -v C:\Users\happy\Documents\purecore-containers\8528a0f48e532396:/home/8528a0f48e532396/data 
      -p 2222:22 -d atmoz/sftp

on my users.conf, I have

8528a0f48e532396:123:1001:100

when I later change the password or remove the user on my users.conf, I'm still able to login using the same credentials

[quiquelhappy]

Please, merge #206