upstream changes (npm/nginx/dependencies) + add eslint

Signed-off-by: Zoey <zoey@z0ey.de>

backend/lib/utils.js

@@ -1,4 +1,5 @@
-const exec = require('child_process').exec;
+const exec     = require('child_process').exec;
+const execFile = require('child_process').execFile;
 
 module.exports = {
 
@@ -16,5 +17,21 @@ module.exports = {
 				}
 			});
 		});
+	},
+
+	/**
+	 * @param   {Array} cmd
+	 * @returns {Promise}
+	 */
+	execFile: function (cmd) {
+		return new Promise((resolve, reject) => {
+			execFile(cmd, function (err, stdout, /*stderr*/) {
+				if (err && typeof err === 'object') {
+					reject(err);
+				} else {
+					resolve(stdout.trim());
+				}
+			});
+		});
 	}
 };