Fix startup with no data (#143)

api/src/server.ts

@@ -2,6 +2,8 @@ import express from "express";
 import cors from "cors";
 import * as Sentry from "@sentry/node";
 import * as Tracing from "@sentry/tracing";
+import fs from "fs";
+import { dataLocation } from "./load-data"
 
 import * as notangles from "./notangles/index";
 import * as freerooms from "./freerooms/index";
@@ -43,6 +45,15 @@ app.use((err, req, res, next) => {
   res.end(res.sentry + "\n");
 });
 
+if(!fs.existsSync(dataLocation)) {
+  fs.writeFile(dataLocation, JSON.stringify({
+    timetableData: {},
+    courseWarnings: [],
+    lastUpdated: 0,
+  }));
+}
+
+
 app.listen(port, () => {
   console.log(`App is running at http://localhost:${port}.`);
   console.log("Press ctrl-c to stop.");