Add postgres code

- Set is currently working
- Other methods to test

Signed-off-by: Lee Smet <lee.smet@hotmail.com>

heromodels/src/db.rs

@@ -4,6 +4,7 @@ use heromodels_core::{Index, Model};
 use serde::{Deserialize, Serialize};
 
 pub mod hero;
+pub mod postgres;
 
 pub trait Db {
     /// Error type returned by database operations.