Add example for streaming posts

Signed-off-by: Vartan Benohanian <vartanbeno@gmail.com>

examples/stream-posts/main.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	"github.com/vartanbeno/go-reddit/reddit"
+)
+
+var ctx = context.Background()
+
+func main() {
+	if err := run(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func run() (err error) {
+	withCredentials := reddit.WithCredentials("id", "secret", "username", "password")
+
+	client, err := reddit.NewClient(nil, withCredentials)
+	if err != nil {
+		return
+	}
+
+	posts, errs, stop := client.Stream.Posts("AskReddit", reddit.StreamInterval(time.Second*3), reddit.StreamDiscardInitial)
+	defer stop()
+
+	go func() {
+		for {
+			select {
+			case post, ok := <-posts:
+				if !ok {
+					return
+				}
+				fmt.Printf("Received post: %s\n", post.Title)
+			case err, ok := <-errs:
+				if !ok {
+					return
+				}
+				fmt.Fprintf(os.Stderr, "Error! %v", err)
+			}
+		}
+	}()
+
+	<-time.After(time.Minute)
+	return
+}