Code + comment cleanup for the entities

ref #39

src/models/entities/Principal.ts

@@ -4,23 +4,27 @@ import { ResponsePrincipal } from '../responses/ResponsePrincipal';
 import { Permission } from './Permission';
 
 /**
- * Defines a admin user.
+ * Defines the principal entity.
+ * A principal basicly is any entity that can receive permissions for the api (users and their groups).
 */
 @Entity()
 @TableInheritance({ column: { name: "type", type: "varchar" } })
 export abstract class Principal {
   /**
-  * autogenerated unique id (primary key).
+  * Autogenerated unique id (primary key).
   */
   @PrimaryGeneratedColumn()
   @IsInt()
   id: number;
 
   /**
-* permissions
-*/
+  * The participant's permissions.
+  */
   @OneToMany(() => Permission, permission => permission.principal, { nullable: true })
   permissions: Permission[];
 
+  /**
+   * Turns this entity into it's response class.
+   */
   public abstract toResponse(): ResponsePrincipal;
 }