Add tools to synchronize with dmlc/tvm (apache#17)

* Add tools to synchronize with dmlc/tvm

dmlc_tvm_commit_id

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+5e3ceaa073f8540eec0e1334a9190041b88921c4

neo-tools/sync-with-dmlc.py

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+import argparse
+import logging
+
+# Install via: pip install GitPython
+from git import Repo
+
+logging.basicConfig(level=logging.INFO)
+
+def parse_args():
+    parser = argparse.ArgumentParser(description='Pull latest commits from dmlc/tvm')
+    parser.add_argument('--sum', dest='accumulate', action='store_const',
+                    const=sum, default=max,
+                    help='sum the integers (default: find the max)')
+
+    return parser.parse_args()
+
+def add_remote(repo, name, url):
+    for remote in repo.remotes:
+        if remote.name == name:
+            assert remote.url == url
+            logging.info("Remote {} already exists".format(name))
+            return
+    logging.info("Add remote {} with url {}".format(name, url))
+    repo.create_remote(name, url)
+
+"""
+This tool automatically cherry picks commit from dmlc/tvm into neo-ai/tvm's dev
+branch, it keeps track of last selected commit id in file dmlc_tvm_commit_id. It
+fetches from dmlc/tvm first, get the latest commit id from master branch, and cherry-picks
+commits from last slected commit until latest commit. 
+"""
+def main():
+    args = parse_args()
+    last_commit_file = 'dmlc_tvm_commit_id'
+    last_commit = None
+    with open(last_commit_file) as f:
+        last_commit = f.read().strip()
+    if last_commit is None:
+        logging.error('can not find last commit file {}'.format(last_commit_file))
+    logging.info('Synchronizing from commit {}'.format(last_commit))
+
+    # Add dmlc/tvm to remote 'upstream' if not
+    repo = Repo()
+    add_remote(repo, 'upstream', 'git@github.com:dmlc/tvm.git')
+
+    # Fetch 'upstream' remote
+    logging.info("Fetching remote upstrean")
+    upstream = repo.remote('upstream')
+    upstream.fetch()
+
+    # Switch to 'master' in 'upstream'
+    repo.git.checkout('upstream/master')
+
+    # Save HEAD commit
+    head = repo.commit('HEAD')
+    head_commit = head.hexsha
+
+    # Switch back to 'dev' branch to do cherry pick
+    repo.git.checkout('dev')
+
+    # Do the cherry-pick from last_commit to head_commit
+    repo.git.cherry_pick('{}..{}'.format(last_commit, head_commit))
+
+    # Update submodule
+    repo.git.submodule('update')
+
+    with open(last_commit_file, 'w') as f:
+        f.write(head_commit)
+
+    logging.info("Update successfully")
+
+if __name__ == '__main__':
+    main()