Fix fish folder overwrite

Make a backup of the existing fish config before inserting custom one.

Install/basic-custom

@@ -8,6 +8,8 @@ mkdir --parents $HOME/.config
 
 # Basic config
 cp --link Templates/config/screenrc $HOME/.config/screenrc
+
+mv $HOME/.config/fish $HOME/.config/fish_stock_backup 
 ln --relative --symbolic Templates/config/fish $HOME/.config/fish
 
 # Export environment variables