As an user, I want to see my old tasks when i re-open the app in order to continue using my to-do list

[linhhonblade]

• [x] I

• [x] N

• [x] V

• [x] E

• [x] S

• [x] T

[dattnguyenn]

• [x] choose the design pattern link graph and link theory
• [x] Store data using textfile link code
• [x] Store data using h2 database link code
• [x] Advantages of database over textfile link => Choose h2 database
• [x] Add library for h2 database and demo for database implementation
  • Link to commit :commit
  • Link to demo : demo
  • How to run demo : README.md
• [x] h2 database manual test link test
• [x] Using Code Smells (Sonarlint extensions powered by IntelliJ) to see all the problems of the code link theory For example
  • Code Smells Within Classes
    • Comment
    • Long Method
  • Code Smells Between Classes
    • Different Interfaces
    • Primitive Obsession
• [x] Refactor code to make it looks neatly
• [x] check the result with the teammate