How can I reference (insert a relative link to) an issue in my github Readme.md?
I found the following document GitHub Flavored Markdown where it is described how to reference to an issue in a commit, but not in the readme.
E.g. if the Issue is: https://github.com/user/project/issues/5 how can I set a link to it in my readme without using absolute links?
This is not (officially) possible. GitHub Flavored Markdown is not used for rendering markdown files in your repo, it is used only for issues and comments. So, readme files are rendered using normal markdown, and no autolinking will happen for issues, SHAs and similar constructs.