add doc and license

LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2021 Kent Ross
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

unsquash.py

@@ -15,6 +15,27 @@
 from github import Github, RateLimitExceededException
 from tqdm import tqdm
 
+__doc__ = """
+-- GitHub Unsquasher --
+This tool rewrites git history for github-hosted repositories, rewriting the
+history as if your pull request squash commits were all merges instead and
+pulling in all the commits of those pull requests into this new branch.
+
+While the commits themselves cannot be exactly reproduced, they were going to be
+rewritten anyway, and the content of the repository is precisely the same. Every
+commit, even if its branch was long deleted or never present in your copy of the
+repo, has its files and trees exactly reproduced (assuming github's API is
+willing to serve the complete data; if you have file versions over 100MB that
+are not already in your repo, this might not work).
+
+This tool can be rerun repeatedly, maintaining an unsquashed branch by updating
+only new commits from the repository! This gives a complete accounting of what
+actually happened, complete with a more comprehensive 'git blame' output for
+all your files. Not only that, but checking out the unsquashed branch is almost
+instant, since when it is up to date it refers to the exact same tree as the
+unsquashed branch.
+"""
+
 
 def main():
     parser = argparse.ArgumentParser(