change file structure

Reviewed-on: #21
Reviewed-by: Get in my car i have candy <huydw@proton.me>

src/app/employee/Employee.ts

@@ -0,0 +1,10 @@
+export class Employee {
+  constructor(public id?: number,
+              public lastName?: string,
+              public firstName?: string,
+              public street?: string,
+              public postcode?: string,
+              public city?: string,
+              public phone?: string) {
+  }
+}