add readme

README.md

@@ -0,0 +1,31 @@
+Bitcask
+----
+
+Bitcask is a log-structured fast KV store.
+
+This project is an implementation of Bitcask written in Go.
+
+[Bitcask intro here](https://riak.com/assets/bitcask-intro.pdf)
+
+## Example
+
+```go
+package main
+
+import (
+	"github.com/qichengzx/bitcask"
+	"log"
+)
+
+func main() {
+	d, err := bitcask.New("your/path/here")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer d.Close()
+
+	d.Put([]byte("bitcask"), []byte("bitcask is a log-structured fast KV store"))
+	v, _ := d.Get([]byte("bitcask"))
+	log.Println(string(v))
+}
+```