Extend database with more tables, rewrite API doc, improve API endpoints

software/backend/models/brand.model.ts

@@ -0,0 +1,14 @@
+import { Column, HasMany, Model, Table } from "sequelize-typescript";
+import { Product } from "./product.model";
+
+@Table({ timestamps: false })
+export class Brand extends Model {
+  @Column
+  name: string
+
+
+  // Relations
+
+  @HasMany(() => Product)
+  products: Product[]
+}