Generate a sitemap for the bitbucket archive

[philipstarkey]

The archive of BitBucket content (optionally) published to GitHub pages is a single page application written in AngularJS. These are not well indexed by Google, and so it is unlikely that the archive will show up in any search results.

This should be able to be worked around by publishing a sitemap and sending it to Google (see https://support.google.com/webmasters/answer/183668?hl=en )

The AngularJS app may also need to be modified to delay rendering until all JSON files are loaded so that Google doesn't capture a half-rendered page (although this needs to be confirmed with a real-world test)