Implemented more stats endpoints

ref #56

src/models/entities/Runner.ts

@@ -58,4 +58,12 @@ export class Runner extends Participant {
   public get distance(): number {
     return this.validScans.reduce((sum, current) => sum + current.distance, 0);
   }
+
+  /**
+   * Returns the total donations a runner has collected based on his linked donations and distance ran.
+  */
+  @IsInt()
+  public get distanceDonationAmount(): number {
+    return this.distanceDonations.reduce((sum, current) => sum + current.amountPerDistance, 0) * this.distance;
+  }
 }