docs: add coming from git guide

[sirodoht]

trafficstars

This is a new guide for learning jujutsu.

I finally made sense of how I can use jujutsu to fit a/the standard github flow. I know there are tons of opinionated guides but I felt this was missing and didn't find it anywhere else. Also, I think it should be part of the official docs -- so here it is!

[google-cla[bot]]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[martinvonz]

I haven't looked at this yet but could you explain how it relates to https://jj-vcs.github.io/jj/latest/tutorial/ (which targets current Git users) and https://jj-vcs.github.io/jj/latest/github/?

[joyously]

From the 0.34.0 CHANGELOG:

Git-based repositories are now colocated by default. Configure git.colocate = false to keep the previous behavior.

[sirodoht]

thanks, both, for reviewing so quickly!

@joyously awesome, thanks! I will adjust

@martinvonz sure! I can explain. I wrote this guide for people who have read about jujutsu and understood the basic idea and want to get started immediately with their working projects.

comparing to the tutorial page (https://jj-vcs.github.io/jj/latest/tutorial/), the guide in this PR:

• goes farther, explains a full code change lifecycle (in the github flow)
• assumes the reader is already familiar with the basic jujutsu concepts (thinking of adding an intro paragraph to explain and link to that)
• assumes an existing local repository with either a clean or even a non-clean working directory (this includes everybody who wants to start learning jujutsu immediately)
• integrates github as part of it and follows the standard github flow explaining a simple PR workflow with changes
• each step is designed not to be verbose, focusing on a single concept/task
• has the purpose of allowing someone to use jujutsu immediately and figure out the rest of the stuff as they go (with this guide being the first step)

comparing to the github page (https://jj-vcs.github.io/jj/latest/github/), the guide in this PR:

• focuses less so on commands completeness or variety of options and potential situations
• explains concepts such as branches/bookmarks as part of the purpose (the tutorial) which makes it more (IHMO!) engaging as one of the first things to read
• explains concepts less verbosely and in much less detail -- which is good for the purpose of this guide but not good for other valuable purposes

the main motivation for writing this guide came because I had a friend explain to me how jujutsu works, but then I found no tutorial on how to start using it in my existing local repository. I think this guide would work well in addition to the existing tutorial, not replacing it, maybe with a title such as "Full lifecycle tutorial".

let me know what you think! happy to make changes, I only submitted this because nothing else I read was useful at this point of my jujutsu experience -- but that's just me!

[sirodoht]

Perfect, thank you @PhilipMetzger! These were all valuable suggestions. I've updated the document with some additional changes as well, and I added an overview section too, which includes the blog post that inspired me to get back to Jujutsu and write this guide.

[sirodoht]

Thanks @joyously! These were great suggestions.

I think how we can integrate this into the existing documentation remains an open question though. I just saw there is also another similar PR from 2 days ago: https://github.com/jj-vcs/jj/pull/7754

I wonder if we can somehow include different approaches but at the same time make it clear which one is for whom 🤔