Add how-to fork and rebase a fork (#370)

Co-authored-by: Steven Liu <[email protected]>
Co-authored-by: Omar Sanseviero <[email protected]>

Author: 3 people

docs/hub/model-repos.md

@@ -142,6 +142,62 @@ $$
 
 $$ E=mc^2 $$
 
+### How can I fork or rebase a repository with LFS pointers?
+
+When you want to fork or [rebase](https://git-scm.com/docs/git-rebase) a repository with [LFS](https://git-lfs.github.com/) files (all files over 20MB are stored as such), you cannot use the usual Git approach since you need to be careful to not break the LFS pointers. Forking can take time depending on your bandwidth, because you will have to fetch an re-upload all the LFS files in your fork.
+
+For example, say you have an upstream repository, **upstream**, and you just created your own repository on the Hub which is **myfork** in this example.
+
+1. Create a destination repository (e.g. **myfork**) in https://huggingface.co 
+
+2. Clone your fork repository
+
+```
+git lfs clone https://huggingface.co/me/myfork.git
+```
+
+3. Fetch non LFS files
+
+```
+cd myfork
+git lfs install --skip-smudge --local # affects only this clone
+git remote add upstream https://huggingface.co/friend/upstream.git
+git fetch upstream
+```
+
+4. Fetch large files. This can take some time depending on your download bandwidth
+
+```
+git lfs fetch --all upstream # this can take time depending on your download bandwidth
+```
+
+4.a. If you want to override completely the fork history (which should only have an initial commit), run:
+
+```
+git reset --hard upstream/main
+```
+
+4.b. If you want to rebase instead of overriding, run the following command and solve any conflicts
+
+```
+git rebase upstream/main
+```
+
+5. Prepare your LFS files to push
+
+```
+git lfs install --force --local # this reinstalls the LFS hooks
+huggingface-cli lfs-enable-largefiles . # needed if some files are bigger than 5Gb
+```
+
+6. And finally push
+
+```
+git push --force origin main # this can take time depending on your upload bandwidth
+```
+
+Now you have your own fork or rebased repo in the Hub!
+
 ## List of license identifiers
 
 Fullname | License identifier (to use in model card)