We are live, to learn about Structs
These are the main points we will discuss today:
1) What are Structs? Type that holds multiple values (similar to tuples, but with key:value pairs)
2) define a struct (out of main) and access fields with dot notation. change value with mutable struct. Print the whole struct
3) build_user function (we can use the init shortcut)
4) create an instance from other instance (single and ..)
5) the move problems
6) tuple structs
7) unit-like structs