Added note, added new init migration

src/entities/character.ts

@@ -31,8 +31,8 @@ export class Character extends BaseEntity {
   chats = new Collection<Chat>(this)
 
   // Position
-  @ManyToOne(() => Zone, { nullable: true })
-  zone?: Zone
+  @ManyToOne()
+  zone!: Zone
 
   @Property()
   positionX = 0
@@ -139,7 +139,7 @@ export class Character extends BaseEntity {
     return this.chats
   }
 
-  setZone(zone: Zone | undefined) {
+  setZone(zone: Zone) {
     this.zone = zone
     return this
   }