fix: database credential access in Docker build

[holtgrewe]

No description provided.

[codecov]

Codecov Report

Merging #90 (56b7c1a) into main (81bfd43) will increase coverage by 11.91%.
The diff coverage is 47.05%.

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #90       +/-   ##
===========================================
+ Coverage   77.37%   89.29%   +11.91%     
===========================================
  Files          85       32       -53     
  Lines        2281      439     -1842     
  Branches      554        0      -554     
===========================================
- Hits         1765      392     -1373     
+ Misses        473       47      -426     
+ Partials       43        0       -43     

Files	Coverage Δ
backend/app/db/session.py	100.00% <ø> (ø)
backend/app/core/config.py	87.50% <47.05%> (-10.84%)	⬇️

... and 53 files with indirect coverage changes