Update readme

README.md

@@ -1,6 +1,10 @@
 # react-native-fast-storage
 
-react-native-fast-storage is a synchronous drop in replacement for `AsyncStorage`.
+react-native-fast-storage is a drop in replacement for `AsyncStorage`.
+
+This library is the React Native implementation of https://github.com/Tencent/MMKV.
+
+It provides very fast read and write access.
 
 ## Getting started
 
@@ -13,7 +17,18 @@ react-native-fast-storage is a synchronous drop in replacement for `AsyncStorage
 ```javascript
 import FastStorage from "react-native-fast-storage";
 
-FastStorage.setItem("key", "Coucou toi");
+await FastStorage.setItem("key", "Coucou toi");
 
-const item = FastStorage.getItem("key"); // Coucou toi
+const item = await FastStorage.getItem("key");
 ```
+
+## Methods
+
+All methods are asynchronous, just like AsyncStorage.
+
+| Prop       |     Params      | Returns  | Description                    |
+| :--------- | :-------------: | :------: | :----------------------------- |
+| setItem    |  `key`, `value` |  `value` |  Allows to set an item         |
+| getItem    |      `key`      |  `value` |  Retrieve the item             |
+| removeItem |      `key`      |   null   |  Remove an item from the store |
+| clearStore |       none      |   null   |  Clear the entire store        |