Grunt - nodemon + watch - gruntjs

Question

i'm new to grunt so i'm guessing i'm doing something simple really wrong. I'm using angular-client-side-auth for my single page app and i wanted to add grunt-contrib-sass and grunt-contrib-watch into Gruntfile.js. Here's the problem, when i start the server using nodemon, the watch never run. I tried concurrent, but no luck.
Here's my Gruntfile.js:
module.exports = function(grunt) {
// Load tasks
grunt.loadNpmTasks('grunt-concurrent');
grunt.loadNpmTasks('grunt-contrib-watch');
grunt.loadNpmTasks('grunt-contrib-sass');
grunt.loadNpmTasks('grunt-contrib-cssmin');
grunt.loadNpmTasks('grunt-mocha-test');
grunt.loadNpmTasks('grunt-env');
grunt.loadNpmTasks('grunt-nodemon');
grunt.loadNpmTasks('grunt-contrib-clean');
//require('load-grunt-tasks')(grunt); // npm install --save-dev load-grunt-tasks
grunt.initConfig({
mochaTest: {
test: {
options: {
reporter: 'spec'
},
src: ['server/tests/**/*.js']
}
},
env : {
options : {
//Shared Options Hash
},
dev : {
NODE_ENV : 'development'
},
test : {
NODE_ENV : 'test'
}
},
nodemon: {
dev: {
script: 'server.js',
}
},
watch: {
//options: { nospawn: true, livereload: true },
sass: {
files: ["client/css/styles.sass"],
tasks: ['sass'],
},
cssmin: {
files: ["client/css/styles.sass"],
tasks: ['cssmin'],
}
},
sass: {
dist: {
files: {
'client/css/styles.css': 'client/css/styles.scss'
}
}
},
cssmin: {
options: {
shorthandCompacting: false,
roundingPrecision: -1
},
target: {
files: [{
expand: true,
cwd: 'client/css',
src: ['styles.css', '!*.min.css'],
dest: 'client/css',
ext: '.min.css'
}]
}
},
concurrent: {
dev: {
options: {
logConcurrentOutput: true
},
tasks: ['watch', 'nodemon:dev']
}
},
clean: ["node_modules", "client/components"]
});
grunt.registerTask('serverTests', ['env:test', 'mochaTest']);
grunt.registerTask('test', ['env:test', 'serverTests']);
grunt.registerTask('dev', ['env:dev', 'concurrent:dev']);
};