Add update readme

README.md

@@ -9,3 +9,31 @@ An API client for the [Notion API](https://developers.notion.com/) implemented i
 - [x] Users
 - [x] Search
 - [ ] Tests and Examples
+
+# Installation
+
+```
+$ go get github.com/jomei/notionapi
+```
+
+# Getting started
+Follow Notion’s [getting started guide](https://developers.notion.com/docs/getting-started) to obtain an Integration Token.
+
+## Example
+
+Make a new `Client`
+
+```go
+import "github.com/jomei/notionapi"
+
+
+client := notionapi.NewClient("your-integration-token")
+```
+Then, use client's methods to retrieve or update your content
+
+```go
+page, err := client.PageRetrieve(context.Background(), "your-page-id")
+if err != nil {
+	// do something
+}
+```