Generally, bots and spiders (as opposed to spam bots) are tools used by search engines which collect documents from the web to build a searchable index for search engines. If you want your board to appear in search engines you need them, they aren't malicious. phpBB, as shipped, is set up to correctly (if you want your board indexed) to handle bots without any changes required.
GitHub wrote:GitHub is a code hosting platform for version control and collaboration. It lets you and others work together on projects from anywhere.
Please visit GitHub
for more information.