add Dockerfile & update README

[bluewings1211]

• 新增 lxml 到 requirments 中
• 新增 dockerfile 並更新 README.md ，讓使用者更方便的使用 twstock cli tools

[mlouielu]

Sorry, but I don't get the point to dockerize a small module, what is the different between this and dockerize?

$ python -m pip install --user twstock
$ twstock -b 2330
四大買賣點判斷 Best Four Point
------------------------------
2330: Buy   量大收紅, 三日均價由下往上

I can accept the README update, but you will need to seperate it into another PR, thanks

[mlouielu]

Is the dockerize of the python module can be used by other docker instance?

[bluewings1211]

OK，當初覺得 README 說明不夠清楚，才 update README 。之後覺得現在 docker 正夯，也許 dockerize 這個 module 之後 push 到 dockerhub 讓更多人使用也是個推廣的方式，增加這個 module 能見度，所以才額外多寫了些內容。

不過你說的沒錯，dockerize 後除了讓一些沒有 python3 且符合環境的人方便使用 CLI 之外沒有太多效益。

我可以重發只有 update README 的 PR

[ianlini]

I agree that docker can help people execute the CLI if they have some issues in their environment., and Docker Hub is even better because you don't need to build the image.

The command python -m pip install --user twstock assumes that people have both python and pip, and they know how to use them correctly.

[fygul]

@bluewings1211

或許你可以維護一個Docker image，放Docker Hub上供需要的人使用。