feat: current bal field on users and corresponding API routes

src/entities/bal.rs

@@ -15,6 +15,12 @@ pub struct Model {
 pub enum Relation {
     #[sea_orm(has_many = "super::book_instance::Entity")]
     BookInstance,
+    #[sea_orm(
+        belongs_to = "super::user::Entity",
+        from = "Column::Id",
+        to = "super::user::Column::CurrentBalId"
+    )]
+    User,
 }
 
 impl Related<super::book_instance::Entity> for Entity {

src/entities/user.rs

@@ -10,6 +10,7 @@ pub struct Model {
     #[sea_orm(unique)]
     pub username: String,
     pub hashed_password: String,
+    pub current_bal_id: Option<u32>,
 }
 
 impl Model {