add readme file and update the git ignore file

Author: Tanzi

.gitignore

@@ -1 +1,3 @@
-__pycache__/
+__pycache__/
+dist/
+*.egg-info/

README.md

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+
+<!-- @import "[TOC]" {cmd="toc" depthFrom=1 depthTo=6 orderedList=false} -->
+
+<!-- code_chunk_output -->
+
+- [1. installation](#1-installation)
+  - [1.1. install with this folder](#11-install-with-this-folder)
+  - [1.2. Install with wheel file](#12-install-with-wheel-file)
+    - [1.2.1. build the wheel file](#121-build-the-wheel-file)
+    - [1.2.2. install the wheel file](#122-install-the-wheel-file)
+- [2. Usage](#2-usage)
+
+<!-- /code_chunk_output -->
+
+# 1. installation
+## 1.1. install with this folder
+Open a command ternimal, and then switch to the project directory(where `setup.py` is). Then use the command below to install
+```bash
+pip install mypackage
+```
+## 1.2. Install with wheel file
+### 1.2.1. build the wheel file
+```bash
+py -m build
+```
+then it will create a folder `dist` and a folder `mypackage.egg-info`
+* there are `*.tar.gz` and `*.whl` in the folder `dist`
+### 1.2.2. install the wheel file
+```bash
+pip install wheel_name.whl
+```
+
+# 2. Usage
+There is a demo:
+* `test.py` in this folder