add missing babel-node package and fix starting js file

Signed-off-by: Jakub Sokołowski <jakub@status.im>

gulpfile.js

@@ -6,7 +6,7 @@ const nodemon = require('gulp-nodemon')
 
 gulp.task('devel', () => {
   nodemon({
-      script: 'src/index.js',
+      script: 'src/app.js',
       presets: ['env', 'stage-2'],
       exec: 'babel-node'
     })

package.json

@@ -13,6 +13,7 @@
   "devDependencies": {
     "@babel/cli": "^7.1.2",
     "@babel/core": "^7.1.2",
+    "@babel/node": "^7.0.0",
     "@babel/plugin-transform-async-to-generator": "^7.1.0",
     "@babel/preset-env": "^7.1.0",
     "gulp": "^3.9.1",