Modify the setup to turn on linting for all git projects.

Summary:
Existing git repos can get the advantage too by running 'git init'.  I
will give instructions for all this once it's in.

Test Plan: Fingers crossed.

Reviewers: benkomalo, alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D2181

.gitconfig

@@ -47,3 +47,6 @@
 
   # Detect renames as well as copies
   renames = copies
+
+[init]
+	templatedir = ~/.git_template

symlink.sh

@@ -16,3 +16,7 @@ for file in .*; do
     fi
     ln -sfvn "$source" "$dest"
 done
+
+# Also create the pre-commit hook git symlink.
+mkdir -p ~/.git_template/hooks
+ln -snf $HOME/khan/devtools/khan-linter/githook.py ~/.git_template/hooks/commit-msg