Runners now use the runnergroup class instead of strings

ref #1

src/models/Runner.ts

@@ -0,0 +1,41 @@
+import {
+    IsInt,
+    IsObject,
+    IsString
+} from "class-validator";
+import { RunnerGroup } from './RunnerGroup';
+
+/**
+ * Defines the contract runner class (from which the runner sponsoring contracts get generated).
+*/
+export class Runner {
+    /**
+     * The runner's id.
+     */
+    @IsInt()
+    id: number;
+
+    /**
+     * The runner's first name.
+     */
+    @IsString()
+    firstname: string;
+
+    /**
+     * The runner's middle name.
+     */
+    @IsString()
+    middlename?: string;
+
+    /**
+     * The runner's last name.
+     */
+    @IsString()
+    lastname: string;
+
+    /**
+     * The runner's group.
+     */
+    @IsObject()
+    group: RunnerGroup;
+}