added handlebars precompile step

step3-gruntfile.js

module.exports = function(grunt) {
  grunt.loadNpmTasks('grunt-ember-template-compiler');

  grunt.initConfig({
    emberhandlebars: {
        compile: {
            options: {
                templateName: function(sourceFile) {
                    var newSource = sourceFile.replace('js/templates/', '');
                    return newSource.replace('.handlebars', '');
                }
            },
            files: ['js/templates/**/*.handlebars'],
            dest: 'js/dist/tmpl.min.js'
        }
    }
  });

  grunt.task.registerTask('local', ['emberhandlebars', 'concat:dist']);
}