tree command

Implement the tree command with find and sed.
Usage

$ git clone https://github.com/yone098/tree.git
$ chmod +x tree/tree
$ tree/tree
/home/yone098/test
|--tree
|  |--.git
|  |  |--HEAD
|  |  |--branches
|  |  |--config
|  |  |--description
|  |  |--hooks
|  |  |  |--applypatch-msg.sample
|  |  |  |--commit-msg.sample
|  |  |  |--post-update.sample
|  |  |  |--pre-applypatch.sample
|  |  |  |--pre-commit.sample
|  |  |  |--pre-push.sample
|  |  |  |--pre-rebase.sample
|  |  |  |--prepare-commit-msg.sample
|  |  |  |--update.sample
|  |  |--index
|  |  |--info
|  |  |  |--exclude
|  |  |--logs
|  |  |  |--HEAD
|  |  |  |--refs
|  |  |  |  |--heads
|  |  |  |  |  |--master
|  |  |  |  |--remotes
|  |  |  |  |  |--origin
|  |  |  |  |  |  |--HEAD
|  |  |--objects
|  |  |  |--0b
|  |  |  |  |--48272afc14c2293262c3d4b3a6004f0fada084
|  |  |  |--20
|  |  |  |  |--9161c1d04c0740b3ebfe79b2f338b9e4f391e2
|  |  |  |--37
|  |  |  |  |--60b40664edf13847ad0cd529a566d1466fa5be
|  |  |  |--59
|  |  |  |  |--092ade14f2e940af77b51b9c929bbecebb6a6e
|  |  |  |  |--8b992a47766c673087a9e2034203ca1229f3f7
|  |  |  |--8e
|  |  |  |  |--06c6b2edbddece6b417229b168288b666f8110
|  |  |  |--8f
|  |  |  |  |--9ede51107a7ba79f62e2ce24a20cba65c1e48a
|  |  |  |--info
|  |  |  |--pack
|  |  |--packed-refs
|  |  |--refs
|  |  |  |--heads
|  |  |  |  |--master
|  |  |  |--remotes
|  |  |  |  |--origin
|  |  |  |  |  |--HEAD
|  |  |  |--tags
|  |--README.md
|  |--tree