Added new service sure finance

[kommandantredundant]

Servicename: Sure Finance

new service

Description

added .env, compose, readme, edited main readme

Related Issues

#314

Verification

working production on a UGREEN NAS, docker compose config checks with no errors

Checklist

• I have performed a self-review of my code and followed the templates structure.
• I have added verification that the stack works as expected.
• I have updated necessary documentation (e.g. frontpage README.md ).
• I have selected the correct label(s) for this PR.

Additional Context

please check proper networking on another device, this was complicated!

[fdbuck0]

I ran into the following error when deploying the sure service:

failed to create network sure_sure_net: Error response from daemon:
invalid pool request: Pool overlaps with other one on this address space

The default subnet (172.28.0.0/16) defined in the example compose.yaml conflicted with an existing Docker network on my host.

Changing the network to an unused subnet solved the problem. For example:

networks:
  sure_net:
    driver: bridge
    ipam:
      config:
        - subnet: 192.168.64.0/20

and updating the static container IPs accordingly:

tailscale: 192.168.64.2
db:        192.168.64.10
redis:     192.168.64.11

as well as the corresponding values in .env:

DB_HOST=192.168.64.10
REDIS_URL=redis://192.168.64.11:6379/1

After these changes, docker compose up -d completed successfully.

It might be useful to mention in the guide that users should verify that the example subnet does not overlap with an existing Docker network (e.g. by running docker network inspect), since many homelab setups already use parts of the 172.x.x.x range.