Update README.md

Author: jviide

README.md

@@ -1,2 +1,61 @@
 # nfq-go
-libnetfilter_queue wrapper for Go
+
+nfq-go is a Go library that wraps libnetfilter_queue.
+
+## Usage
+
+### Import 
+
+```go
+import nfq "github.com/hownetworks/nfq-go"
+```
+
+### New
+
+```go
+queue, err := nfq.New(0, func(pkt nfq.Packet) {
+  ...
+})
+```
+
+### Give a Verdict
+
+`NF_ACCEPT`
+
+```go
+err := pkt.Accept()
+```
+
+`NF_DROP`
+
+```go
+err := pkt.Drop()
+```
+
+`NF_REPEAT`
+
+```go
+err := pkt.Repeat()
+```
+
+`NF_QUEUE` to queue 5
+
+```go
+err := pkt.Queue(x)
+```
+
+### Modifying Packets
+
+Use `WithData(data []byte)` and `WithMark(mark uint32)` to modify the packet's data and mark. Instead of modifying the original these methods return a new `Packet` and can be chained.
+
+As an example, here's how to (re)queue the packet to queue number 5, this time its data set to `newData` and mark set to `1234`:
+
+```go
+err := pkt.WithData(newData).WithMark(1234).Queue(5)
+```
+
+### Close
+
+```go
+queue.Close()
+```