Add a no commit to specific branch hook. (#185)

* add no commit code and config

* add the code

* remove version tweak

* fix logic, remove newline

* add Tests and cleanup testing issues

* remove extraneous modules

* cleanup some pep8 and flake issues

* reorder imports

* more fixes for syntax checking

* code cleanup based off asottile comments

* Use Contractions Properly, alphabatize new hook.

* Adding support for branches with a slash in them.

pre_commit_hooks/no_commit_to_branch.py

@@ -0,0 +1,25 @@
+from __future__ import print_function
+
+import argparse
+import sys
+
+from pre_commit_hooks.util import cmd_output
+
+
+def is_on_branch(protected):
+    branch = cmd_output('git', 'symbolic-ref', 'HEAD')
+    chunks = branch.strip().split('/')
+    return '/'.join(chunks[2:]) == protected
+
+
+def main(argv=[]):
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '-b', '--branch', default='master', help='branch to disallow commits to')
+    args = parser.parse_args(argv)
+
+    return int(is_on_branch(args.branch))
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))