README: style syntax to markdown

Change-Id: Idf5fb2adf1622f7d729146200c35f7cae4d7434c
Reviewed-on: https://go-review.googlesource.com/57334
Reviewed-by: Andrew Bonventre <andybons@golang.org>
diff --git a/README b/README
deleted file mode 100644
index 9563464..0000000
--- a/README
+++ /dev/null
@@ -1,7 +0,0 @@
-This repository holds machine architecture information used by the Go toolchain.
-The parts needed in the main Go repository are copied in.
-
-This repository requires Go 1.6, or Go 1.5 with the vendor experiment enabled:
-
-	export GO15VENDOREXPERIMENT=1
-
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..a7d334d
--- /dev/null
+++ b/README.md
@@ -0,0 +1,6 @@
+# arch
+
+This repository holds machine architecture information used by the Go toolchain.
+The parts needed in the main Go repository are copied in.
+
+This repository requires Go 1.5+ with the vendor experiment enabled.