Add Gruntfile.

Gruntfile.coffee

@@ -0,0 +1,62 @@
+module.exports = (grunt) ->
+
+  grunt.initConfig
+    pkg: require './package'
+    coffee:
+      src:
+        expand: true
+        cwd: 'src'
+        src: '**/*.coffee'
+        dest: 'lib'
+        ext: '.js'
+      index:
+        src: 'index.coffee'
+        dest: 'index.js'
+    coffeelint:
+      src:
+        src: '<%= coffee.src.cwd %>/<%= coffee.src.src %>'
+      index:
+        src: '<%= coffee.index.src %>'
+      test:
+        src: 'test/**/*.coffee'
+      gruntfile:
+        src: 'Gruntfile.coffee'
+    jsonlint:
+      packagejson:
+        src: 'package.json'
+    watch:
+      src:
+        files: '<%= coffee.src.cwd %>/<%= coffee.src.src %>'
+        tasks: ['coffeelint:src', 'test']
+      index:
+        files: '<%= coffee.index.src %>'
+        tasks: ['coffeelint:index', 'test']
+      test:
+        files: '<%= coffeelint.test.src %>',
+        tasks: ['coffeelint:test', 'test']
+      gruntfile:
+        files: '<%= coffeelint.gruntfile.src %>'
+        tasks: ['coffeelint:gruntfile']
+      packagejson:
+        files: '<%= jsonlint.packagejson.src %>'
+        tasks: ['jsonlint:packagejson']
+    exec:
+      mocha:
+        options: [
+          '--compilers coffee:coffee-script'
+          '--reporter spec'
+          '--colors'
+          '--recursive'
+        ],
+        cmd: './node_modules/.bin/mocha <%= exec.mocha.options.join(" ") %>'
+
+  grunt.loadNpmTasks 'grunt-contrib-coffee'
+  grunt.loadNpmTasks 'grunt-coffeelint'
+  grunt.loadNpmTasks 'grunt-jsonlint'
+  grunt.loadNpmTasks 'grunt-contrib-watch'
+  grunt.loadNpmTasks 'grunt-notify'
+  grunt.loadNpmTasks 'grunt-exec'
+
+  grunt.registerTask 'test', ['jsonlint', 'coffeelint', 'exec:mocha']
+  grunt.registerTask 'build', ['coffee']
+  grunt.registerTask 'default', ['test']