Why build periodically?

In most cases, if the code hasn't changed, there is no reason to build. However, in some cases, something external to the code may cause it to fail. For example, if I scrape information from a website, that scraper code will fail if the website undergoes a redesign. I want to know about that failure, so that I can fix the code.

In #travis, @svenfuchs suggested that I open a ticket and ping @rkh about this new feature.

In terms of implementation, it was mentioned:

svenfuchs: i'd feel we'd look for an external solution that pings our listener just like github does but maybe konstantin has other ideas, too

I propose the interval be set in .travis.yml in either crontab format (0 0 * * 0) or words like daily, weekly, etc.