Update README.md and license. Add examples

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

examples/submit-post/main.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"github.com/vartanbeno/go-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
+	}
+
+	post, _, err := client.Post.SubmitText(ctx, reddit.SubmitTextOptions{
+		Subreddit: "test",
+		Title:     "This is a title",
+		Text:      "This is some text",
+	})
+	if err != nil {
+		return
+	}
+
+	fmt.Printf("The text post is available at: %s\n", post.URL)
+
+	post, _, err = client.Post.SubmitLink(ctx, reddit.SubmitLinkOptions{
+		Subreddit: "test",
+		Title:     "This is a title",
+		URL:       "http://example.com",
+		Resubmit:  true,
+	})
+	if err != nil {
+		return
+	}
+
+	fmt.Printf("The link post is available at: %s\n", post.URL)
+
+	return
+}