[Docs]: Add some more documentation on how to work with github.

The document roughly describes some workflows, which help new users
to start with github.

docs/github.md

@@ -0,0 +1,90 @@
+# Using Jujutsu with GitHub Projects
+
+This guide assumes a basic understanding of either Git or Mercurial. 
+
+## Setup an SSH key
+As of December 2022 it's recommended to set up a ssh key to work with Github
+projects. See [Github's Tutorial][gh]. This restriction may be lifted in the 
+future, see [issue #469][http-auth] for more information and progress on authenticated http. 
+
+
+## Basic workflows
+You can either create a branch and then commit revisions on top of it (similiar 
+to how Git is typically used) or just start making changes in the repository
+(which is how Mercurial is used). 
+This allows you to continue using your favorite way of using the VCS. 
+
+It's also possible to just commit multiple changes and set the expected branch 
+retroactively. 
+
+**Notable Differences to other VCS**  
+Branches do not move forward when creating commits on top. This means you should
+set the current branch to work on before starting your work. 
+
+### Git workflow
+
+```shell script
+$ jj branch create $your-feature
+$ # Do your work
+$ jj commit -m "feat(xy): some thing"
+$ jj git push # Note: Jujutsu defaults to pushing all branches
+```
+
+### Mercurial Workflow
+
+```shell script
+$ nvim docs/toolchain.md 
+$ jj commit -m "Docs: Update toolchain description"
+$ # Do some more work
+$ jj branch create $your-feature
+$ # move all commits to your feature-branch.
+$ jj branch set $your-feature -r 'remote_branches()..@' 
+```
+
+This allows you to retroactively move the new revisions, to your feature branch.
+
+## Updating the repository.
+As of December 2022, Jujutsu has no equivalent to a `git pull` command.
+Until such a command is added, you need to use `jj git fetch` followed by a 
+`jj git rebase -d $main_branch` to update your changes. 
+
+## Working in a Git co-located repository
+After doing `jj init --git-repo=.`, git will be in a detached HEAD state,
+which is unusual, as git mainly works with branches. 
+In a co-located repository, `jj` isn't the source of truth. But since Jujutsu
+allows a incremental migration, since `jj commit` updates the HEAD of the git
+repository. 
+
+
+Although `jj git import` and `jj git export` exist for co-located repositories,
+they should only be used in case of an unrecoverable error.
+
+```shell script
+$ 
+$ 
+$ 
+```
+
+## Working in a Jujutsu repository
+In a Jujutsu repository, the workflow is simplified. If there's no need for 
+explicitly named branches, you just can generate one for a change. As Jujutsu 
+is able to create a branch for a revision.
+
+```shell script
+$ ij . 
+$ # Do your work
+$ jj commit
+$ # Jujutsu automatically creates a branch
+$ jj git push -c $revision
+```
+
+
+## Useful Revsets
+
+
+## Merge conflicts
+
+For a detailed overview, how Jujutsu handles conflicts, revisit the [tutorial][tutorial.md#Conflicts].
+
+[gh]: https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent
+[http-auth]: https://github.com/martinvonz/jj/issues/469