So on the 3rd day, man i have to say this is horrific. In the morning, I learn about postgresql, diagram the database then create it with sqlshell (I thought postgresql don't have sql editor). After re-type plenty of long query line because of couple syntax error, I finally nailed it. Just to realise that it have sql editor. But everything is ok because after that I dive into spring boot. I starting to learn about Spring Security and JWT using jjwt, learning how it work, how it encode, what encode, key,... do I used. Setting up the project with MVC model then implement JWT Utils class, I called it a day at 1:30AM.