Added distance Donation

src/models/DistanceDonation.ts

@@ -0,0 +1,42 @@
+import { Entity, Column } from "typeorm";
+import { IsInt, IsNotEmpty, IsPositive,} from "class-validator";
+import { Donation } from "./Donation";
+import { Runner } from "./Runner";
+
+/**
+ * Defines a distance based donation.
+ * Here people donate a certain amout per kilometer
+*/
+@Entity()
+export class DistanceDonation extends Donation {
+  /**
+   * The runner associated.
+   */
+  @Column()
+  @IsNotEmpty()
+  //TODO:Relation
+  runner: Runner;
+
+  /**
+   * The amount the donor set to be donated per kilometer that the runner ran.
+   */
+  @Column()
+  @IsInt()
+  @IsPositive()
+  amountPerDistance: number;
+
+  /**
+   * The donation's amount in cents (or whatever your currency's smallest unit is.).
+   * The exact implementation may differ for each type of donation.
+   */
+  @IsInt()
+  public get amount(): number {
+    let calculatedAmount = -1;
+    try {
+      calculatedAmount = this.amountPerDistance * this.runner.getDistance();
+    } catch (error) {
+      throw error;
+    }
+    return calculatedAmount;
+  }
+}