Create .mailmap file

Use .mailmap file to coalesce commits
by the same person using multiple names and/or email addresses

Change-Id: I00c060d62a4671ca6ce0a5e04ac3c4f144ed671e
diff --git a/.mailmap b/.mailmap
new file mode 100644
index 0000000..d5ad780
--- /dev/null
+++ b/.mailmap
@@ -0,0 +1,4 @@
+# Format is:
+# <preferred e-mail> <other e-mail 1>
+# <preferred e-mail> <other e-mail 2>
+Jiajun Liu <jiajun@unitedstack.com> <iamljj@gmail.com>