Implemented the donation response

ref #66

src/models/entities/FixedDonation.ts

@@ -1,5 +1,6 @@
 import { IsInt, IsPositive } from "class-validator";
 import { ChildEntity, Column } from "typeorm";
+import { ResponseDonation } from '../responses/ResponseDonation';
 import { Donation } from "./Donation";
 
 /**
@@ -11,16 +12,33 @@ export class FixedDonation extends Donation {
 
   /**
    * The donation's amount in cents (or whatever your currency's smallest unit is.).
+   * This is the "real" value used by fixed donations.
    */
   @Column()
   @IsInt()
   @IsPositive()
-  amount: number;
+  private _amount: number;
+
+  /**
+   * The donation's amount in cents (or whatever your currency's smallest unit is.).
+   */
+  @IsInt()
+  @IsPositive()
+  public get amount(): number {
+    return this._amount;
+  }
+
+  /**
+   * The donation's amount in cents (or whatever your currency's smallest unit is.).
+   */
+  public set amount(value: number) {
+    this._amount = value;
+  }
 
   /**
    * Turns this entity into it's response class.
    */
-  public toResponse() {
-    return new Error("NotImplemented");
+  public toResponse(): ResponseDonation {
+    return new ResponseDonation(this);
   }
 }