Update README.md

Author: yjg30737

README.md

@@ -1,2 +1,34 @@
 # pyqt-foldable-window
 PyQt foldable window
+
+## Requirements
+PyQt5 >= 5.8
+
+## Setup
+```pip3 install git+https://github.com/yjg30737/pyqt-foldable-window.git --upgrade```
+
+## Example
+```python
+from PyQt5.QtWidgets import QApplication, QTextEdit
+from pyqt_foldable_window import FoldableWindow
+
+
+if __name__ == "__main__":
+    import sys
+
+    app = QApplication(sys.argv)
+    window = FoldableWindow()
+    window.layout().addWidget(QTextEdit()) # QTextEdit is center widget in this example.
+    window.show()
+    app.exec_()
+```
+
+Result
+
+Unfolded state
+
+![image](https://user-images.githubusercontent.com/55078043/148364015-c8b7ae03-4004-4940-a8d3-655e32e0bbd5.png)
+
+Folded state
+
+![image](https://user-images.githubusercontent.com/55078043/148364439-3ffeaad8-5a6f-4e80-bd03-8bd498255b03.png)