Visual Studio Code: gulp is not recognized, added to path - json

Question

I trying to set up an project with pre processing with gulp in Visual Studio Code.
I have installed gulp using npm: npm install gulp --save en installed it also globally.
Added some tasks in my gulpfile.js and filled the tasks.json file in Studio Code with details.
When I run the scripts, Studio keep saying 'gulp is not recognized as an internal of external command'. I have add 'NODE_PATH' as system variabele, and i'm able to start gulp manually via command line. (npm run gulp).
What I'm doing wrong?
What I did so far:
Added script: gulp:gulp to my package.json (as seen on https://stackoverflow.com/a/32569658/4548006)
Installed modules:
npm
gulp
gulp-styles
gulp-uglify
gulp-pug
gulp-pug2
gulpfile.js
var gulp = require('gulp');
var uglify = require('gulp-uglify');
var pump = require('pump');
var pug = require('gulp-pug2');
var stylus = require('gulp-stylus');
gulp.task('default', function(){
gulp.watch([
'app/app.js',
'app/routes/routes.js',
'app/controllers/**.js',
'app/directives/**.js',
'app/services/**.js',
'app/libs/**.js',], ['scripts', 'scripts-minify']);
gulp.watch([
'app/partials/**.pug',
'app/index.pug'], ['views-compile']);
gulp.watch([
'app/style/**.style'], ['stylus']);
})
gulp.task('stylus', function(){
return gulp.src([
'app/style/**.style'
])
.pipe(stylus({
compress:true
}))
.pipe(gulp.dest('app/views/css/'))
})
gulp.task('views-compile', function(){
return gulp.src([
'app/partials/**.pug',
'app/index.pug'
])
.pipe(pug.compile())
.pipe(gulp.dest('app/views'))
})
gulp.task('scripts', function(){
return gulp.src([
'app/app.js',
'app/routes/routes.js',
'app/controllers/**.js',
'app/directives/**.js',
'app/services/**.js',
'app/libs/**.js']
)
.pipe(concat('scripts.js'))
.pipe(gulp.dest('app/scripts/'))
})
gulp.task('scripts-minify', function(){
return gulp.src([
'app/scripts/scripts.js']
)
.pipe(concat('scripts.min.js'))
.pipe(uglify())
.pipe(gulp.dest('app/scripts/'))
});
Tasks.json
{
"version": "0.1.0",
"command": "gulp",
"isShellCommand": true,
"tasks": [
{
"taskName": "default",
"isBuildCommand": true,
"showOutput": "always",
"isWatching": true
}
]
}