File access errors on mints.json and tokens.json

[TheFockinFury]

Describe the bug
When running the latest version in docker, I see file access errors repeatedly in the container's console:

[Error: ENOENT: no such file or directory, open './data/mints.json'] {
�
  errno: -2,
  code: 'ENOENT',
  syscall: 'open',
  path: './data/mints.json'
}
[Error: EACCES: permission denied, open './tokens.json'] {
  errno: -13,
  code: 'EACCES',
  syscall: 'open',
  path: './tokens.json'
}

To Reproduce
Steps to reproduce the behavior:

1. Deploy nutstash-wallet:0.1.11-d
2. Access the web UI on whatever port you exposed
3. Enable selfhosted backup option in 'settings'
4. Add some mints, receive some tokens
5. Browse to a few more pages in the wallet

Expected behavior
No errors

Desktop (please complete the following information):

• OS: Linux container running in Proxmox VE 7.3-3 (Debian 11)
• All browsers
• Docker 23.0.3
• Nutstash 0.1.11-d