Redmine

A plugin to send email digests of project activity. This plugin may be called by a scheduler (cronjob, Windows task, rufus-scheduler, etc.) or run manually from the plugin's configuration page.

A scheduler of some kind is needed to call the digest automatically (although a means is provided to create the digests manually).

The readme provides some examples for various scheduler command lines (cron job, Windows task, or rufus-scheduler).

After the plugin is installed, the readme is available from the plugin's configuration page (Administration > Plugins > Digest > Configure > Readme).

I had not written (or read) a lick of Ruby code until last week, so improvement patches are definitely welcome.