I have only added some git aliases of commands that I often use daily. It is located at: ./.config/fish/functions/git_aliases.fish
I've added some hack to WSL users to enable fish shell at autostart. It is related to .bashrc in this project. So for me the solution is to overwrite this file on every new WSL installation.
cp ./.bashrc ~
So you probably only need to copy these lines from my .bashrc to your:
if [ -t 1 ]; then
exec fish
fi
So it is my initial configuration, that I've created by some manuals. Full description and improvements will be there later