fix error, remove stuff, add stuff

frontend/src/app.js

@@ -0,0 +1,21 @@
+const express = require( 'express' );
+let app = express();
+const path = require( 'path' );
+const fs = require( 'fs' );
+const bodyParser = require( 'body-parser' );
+const exec = require( 'child_process' ).exec;
+
+app.use( bodyParser.urlencoded( { extended: false } ) );
+app.use( bodyParser.json() );
+
+function execute(command, callback){
+    exec(command, function(error, stdout, stderr){ callback(stdout); });
+};
+
+app.get( '/api/getEngines', ( request, response ) => {
+    execute( 'ImageVideoUpscaler-cli -p', out => {
+        response.send( out );
+    } );
+} );
+
+app.listen( 8081 );