Attempt #1 to fix CORS issue and docker build.

docker/nginx.conf

@@ -30,8 +30,6 @@ http {
 
             # CORS headers
             add_header 'Access-Control-Allow-Origin' '*';
-            add_header 'Access-Control-Allow-Methods' 'GET, POST';
-            add_header 'Access-Control-Allow-Headers' 'Content-Type, Accept';
         }
 
         # Error pages

src/backend/server.cjs

@@ -6,9 +6,7 @@ const server = http.createServer();
 const io = socketIo(server, {
     cors: {
         origin: "*",
-        methods: ["GET", "POST"],
-        allowedHeaders: ["Content-Type", "Accept"],
-        credentials: false
+        methods: ["GET", "POST"]
     }
 });