diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..39c3d24
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) NJUCSE17 and its affiliates.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..16495ca
--- /dev/null
+++ b/README.md
@@ -0,0 +1,51 @@
+# JB-App
+
+Mobile application of [JB-Online](https://github.com/NJUCSE17/JB-Online). Built with React Native and Expo.
+
+Legacy (Java) version of this app can be found at [JB-App-Legacy](https://github.com/NJUCSE17/JB-App-Legacy), but it is no longer maintained.
+
+## Getting Started
+
+### Project Structure
+
+```
++-assets     -> Save fonts and images
+|-components -> Reusable single components
+|-constants  -> Theme, style and other constants
+|-navigation -> Routes and navigation config
+|-screens    -> Screens of navigation
+|-services   -> API and its config
+|-App.js     -> Main entrance of this app
+`-app.json   -> APP related config
+```
+
+### Run, Test and Build
+
+- Please use yarn instead of npm as package manager.
+- Run `yarn start` or `expo start` to start development server.
+- Keep `/services/config.json` excluded from git.
+- Run `expo build:[platform]` to build a standalone app.
+
+References:
+
+- [React Native documentation](https://facebook.github.io/react-native/docs/getting-started.html)
+- [Expo documentation](https://docs.expo.io/)
+- [Native Base documentation](https://docs.nativebase.io)
+
+### JavaScript is Bad!
+
+You can use TypeScript instead. We are considering changing all JS files to TS.
+
+## License and Credit
+
+JB-App is MIT licensed.
+
+Credits to
+
+- [Axios](https://github.com/axios/axios)
+- [Expo](https://expo.io) and Expo SDK
+- [js-base64](https://github.com/dankogai/js-base64) by dankogai
+- [Native Base](https://github.com/GeekyAnts/NativeBase) by GeekyAnts
+- [qs](https://github.com/ljharb/qs) by ljharb
+- [React Native](https://github.com/facebook/react-native) by Facebook
+- Icon from FlatIcon and FontAwesome
\ No newline at end of file
diff --git a/app.json b/app.json
index 64b85e6..f237570 100644
--- a/app.json
+++ b/app.json
@@ -8,7 +8,7 @@
       "ios",
       "android"
     ],
-    "version": "0.2.2",
+    "version": "0.2.3",
     "orientation": "portrait",
     "icon": "./assets/images/icon.png",
     "splash": {
diff --git a/package.json b/package.json
index cb92672..416f85d 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,7 @@
     "expo": "^32.0.0",
     "js-base64": "^2.5.1",
     "native-base": "^2.12.0",
-    "querystring": "^0.2.0",
+    "qs": "^6.6.0",
     "react": "16.5.0",
     "react-native": "https://github.com/expo/react-native/archive/sdk-32.0.0.tar.gz",
     "react-native-htmlview": "^0.13.0",
diff --git a/services/api.js b/services/api.js
index e0a7976..f9eda5b 100644
--- a/services/api.js
+++ b/services/api.js
@@ -1,7 +1,7 @@
 import axios from 'axios';
 import { Alert, AsyncStorage } from 'react-native';
 import { Constants } from 'expo';
-import { stringify } from 'querystring';
+import { stringify } from 'qs';
 import { Base64 } from 'js-base64';
 
 import * as Config from './config';
diff --git a/yarn.lock b/yarn.lock
index 35c7fba..df3a7a6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5649,7 +5649,7 @@ punycode@^2.1.0, punycode@^2.1.1:
   resolved "http://registry.npm.taobao.org/punycode/download/punycode-2.1.1.tgz#b58b010ac40c22c5657616c8d2c2c02c7bf479ec"
   integrity sha1-tYsBCsQMIsVldhbI0sLALHv0eew=
 
-qs@^6.5.0:
+qs@^6.5.0, qs@^6.6.0:
   version "6.6.0"
   resolved "http://registry.npm.taobao.org/qs/download/qs-6.6.0.tgz#a99c0f69a8d26bf7ef012f871cdabb0aee4424c2"
   integrity sha1-qZwPaajSa/fvAS+HHNq7Cu5EJMI=
@@ -5667,11 +5667,6 @@ query-string@^6.2.0:
     decode-uri-component "^0.2.0"
     strict-uri-encode "^2.0.0"
 
-querystring@^0.2.0:
-  version "0.2.0"
-  resolved "http://registry.npm.taobao.org/querystring/download/querystring-0.2.0.tgz#b209849203bb25df820da756e747005878521620"
-  integrity sha1-sgmEkgO7Jd+CDadW50cAWHhSFiA=
-
 raf@^3.1.0:
   version "3.4.1"
   resolved "http://registry.npm.taobao.org/raf/download/raf-3.4.1.tgz#0742e99a4a6552f445d73e3ee0328af0ff1ede39"