add git aliases

gitconfig

@@ -8,3 +8,12 @@
 	status = auto
 [core]
 	autocrlf = input
+[alias]
+    st = status
+    co = checkout
+	cm = commit
+    br = branch
+    llog = log --date=local
+    changes = diff --name-status -r
+    diffstat = diff --stat -r
+    lg = log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --date=relative