Default to example config

[marwan-at-work]

config.toml is git ignored and so the docker build will fail when merging to master.
We should default to the config.example.toml then let the user specify their own config on docker run if they want to.

[codecov-io]

Codecov Report

Merging #678 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #678   +/-   ##
=======================================
  Coverage   44.24%   44.24%           
=======================================
  Files         105      105           
  Lines        3232     3232           
=======================================
  Hits         1430     1430           
  Misses       1665     1665           
  Partials      137      137

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