[Migration] Needs some tabs

docs/i_u_m_migration.md

@@ -32,8 +32,13 @@ rsync -aHhP --numeric-ids --delete /var/lib/docker/volumes/ root@some.other.mach
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 **4\.**    Shut down Mailcow via `docker-compose down` and stop Docker on the source machine.
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 **5\.**    Repeat step 3 with the same commands (this will be much quicker than the first time).
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 **6\.**    Start docker on the target machine `systemctl start docker.service`.
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 **7\.**    Go into the /opt/mailcow-dockerized directory and run `docker-compose pull`.
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 **8\.**    Start the whole mailcow stack with `docker-compose up -d` and everything should be fine.
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 **9\.**    Change your DNS settings.