Show the feed of a given URL and wait for new entries appearing at the bottom

`tail` for RSS feeds.
More information: <https://github.com/gvalkov/rsstail.py>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

rsstail -u {{url}}

click the source code to copy install rsstail on any operating system with command-not-found.com