If a project has to have multiple git repos (e.g. Bitbucket and Github) then it's better that they remain in sync.
Usually this would involve pushing each branch to each repo in turn, but actually Git allows pushing to multiple repos in one go.
If in doubt about what git is doing when you run these commands, just
GitHub supports several lightweight markup languages for documentation; the most popular ones (generally, not just at GitHub) are Markdown and reStructuredText. Markdown is sometimes considered easier to use, and is often preferred when the purpose is simply to generate HTML. On the other hand, reStructuredText is more extensible and powerful, with native support (not just embedded HTML) for tables, as well as things like automatic generation of tables of contents.