Fixed the controller not waiting for initialization

ref #5

src/controllers/PdfController.ts

@@ -11,10 +11,15 @@ import { PdfCreator } from '../PdfCreator';
 @JsonController()
 export class PdfController {
     private pdf: PdfCreator = new PdfCreator();
+    private initialized: boolean = false;
 
     @Post('/contracts')
     @OpenAPI({ description: "Generate Sponsoring contract pdfs from runner objects.<br>You can choose your prefered locale by passing the 'locale' query-param." })
     async generateContracts(@Body({ validate: true }) runners: Runner | Runner[], @Res() res: any, @QueryParam("locale") locale: string) {
+        if (!this.initialized) {
+            await this.pdf.init();
+            this.initialized = true;
+        }
         if (!Array.isArray(runners)) {
             runners = [runners];
         }