Tilde ~ symbol in path is not expanded

[ddddbug]

• ruby -v

ruby 2.7.8p225 (2023-03-30 revision 1f4d455848) [x86_64-linux-musl]

• transmission-rss -v

1.2.3

• The content for your configuration file. You can anonymize URLs if the
  issue is independent of the feed contents.

seen_file: ~/.config/transmission/seen

• Relevant lines from log output.

docker exec -it transmission-rss-1 bash # host
bash-5.1# find | grep seen 2> /dev/null # in docker
./usr/local/bundle/gems/transmission-rss-1.2.3/lib/transmission-rss/seen_file.rb
./~/.config/transmission/seen
bash-5.1# file ~
/root: directory
bash-5.1# file \~
~: director

Path ~/.config/transmission/seen is suggested in README, however the tilde ~ symbol is not correctly expanded to the root user home path, hence a directory named ~ (literally) will be created under root directory within the docker. E.g., as if the following has been executed

mkdir -p /\~/.config/transmission/
touch /\~/.config/transmission/seen

I don't code in Ruby, but a fix should be easy: https://www.rubydoc.info/stdlib/core/File.expand_path
Or we should update the README, so people don't fall into this loophole...

Cheers.