Updated Gruntfile

Gruntfile2.js

module.exports = function(grunt) {

  // Project configuration.
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    uglify: {
      options: {
        banner: '/*! <%= pkg.name %> <%= grunt.template.today("yyyy-mm-dd") %> */\n'
      },
      build: {
          files: [
              {
                expand: true,
                cwd: '<%= pkg.apps.main.js %>',
                src: ['*.js'],
                dest: '<%= pkg.apps.main.js %>/min/',
                ext: '.min.js',
                extDot: 'last'
              },
              {
                  expand: true,
                  cwd: '<%= pkg.apps.papers.js %>',
                  src: ['*.js'],
                  dest: '<%= pkg.apps.papers.js %>/min/',
                  ext: '.min.js',
                  extDot: 'last'
              },
              {
                  expand: true,
                  cwd: '<%= pkg.apps.account.js %>',
                  src: ['*.js'],
                  dest: '<%= pkg.apps.account.js %>/min/',
                  ext: '.min.js',
                  extDot: 'last'
              },
              {
                  expand: true,
                  cwd: '<%= pkg.apps.classes.js %>',
                  src: ['*.js'],
                  dest: '<%= pkg.apps.classes.js %>/min/',
                  ext: '.min.js',
                  extDot: 'last'
              }
          ]
      }
    },
    coffee: {
        compile: {
            files: [
                {
                  expand: true,
                  cwd: '<%= pkg.apps.main.coffee %>',
                  src: ['*.coffee'],
                  dest: '<%= pkg.apps.main.js %>/',
                  ext: '.js',
                  extDot: 'last'
              },
              {
                  expand: true,
                  cwd: '<%= pkg.apps.papers.coffee %>',
                  src: ['*.coffee'],
                  dest: '<%= pkg.apps.papers.js %>/',
                  ext: '.js',
                  extDot: 'last'
              },
              {
                  expand: true,
                  cwd: '<%= pkg.apps.account.coffee %>',
                  src: ['*.coffee'],
                  dest: '<%= pkg.apps.account.js %>/',
                  ext: '.js',
                  extDot: 'last'
              },
              {
                  expand: true,
                  cwd: '<%= pkg.apps.classes.coffee %>',
                  src: ['*.coffee'],
                  dest: '<%= pkg.apps.classes.js %>/',
                  ext: '.js',
                  extDot: 'last'
              }
            ]
        }
    },
    compass: {
        main: {
            options: {
                sassDir: '<%= pkg.apps.main.sass %>',
                cssDir: '<%= pkg.apps.main.css %>',
                noLineComments: true,
                outputStyle: 'compressed'
            }
        },
        papers: {
            options: {
                sassDir: '<%= pkg.apps.papers.sass %>',
                cssDir: '<%= pkg.apps.papers.css %>',
                noLineComments: true,
                outputStyle: 'compressed'
            }
        },
        account: {
            options: {
                sassDir: '<%= pkg.apps.account.sass %>',
                cssDir: '<%= pkg.apps.account.css %>',
                noLineComments: true,
                outputStyle: 'compressed'
            }
        },
        classes: {
            options: {
                sassDir: '<%= pkg.apps.classes.sass %>',
                cssDir: '<%= pkg.apps.classes.css %>',
                noLineComments: true,
                outputStyle: 'compressed'
            }
        }
    },
    watch: {
        coffee: {
          files: ['**/*.coffee'],
          tasks: ['coffee', 'uglify']
        },
        sass: {
          files: ['**/*.scss'],
          tasks: ['compass']
        }
    },
    clean: {
        main: ['<%= pkg.apps.main.js %>/*.js', '<%= pkg.apps.main.sass %>', '<%= pkg.apps.main.coffee %>'],
        papers: ['<%= pkg.apps.papers.js %>/*.js', '<%= pkg.apps.papers.sass %>', '<%= pkg.apps.papers.coffee %>'],
        account: ['<%= pkg.apps.account.js %>/*.js', '<%= pkg.apps.account.sass %>', '<%= pkg.apps.account.coffee %>'],
        classes: ['<%= pkg.apps.classes.js %>/*.js', '<%= pkg.apps.classes.sass %>', '<%= pkg.apps.classes.coffee %>']
    }
  });


  grunt.loadNpmTasks('grunt-contrib-uglify');
  grunt.loadNpmTasks('grunt-contrib-coffee');
  grunt.loadNpmTasks('grunt-contrib-compass');
  grunt.loadNpmTasks('grunt-contrib-watch');
  grunt.loadNpmTasks('grunt-contrib-clean');

  // Default task(s).
  grunt.registerTask('default', ['coffee', 'uglify', 'compass']);

};