diff --git a/.gitignore b/.gitignore
index daa6029..b7058f7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 test.js
+node_modules
diff --git a/Gruntfile.js b/Gruntfile.js
new file mode 100644
index 0000000..4f4dca9
--- /dev/null
+++ b/Gruntfile.js
@@ -0,0 +1,22 @@
+module.exports = function (grunt) {
+  grunt.initConfig({
+    tape: {
+      options: {
+        pretty: false,
+        output: 'console'
+      },
+      files: ['test/**/*.js']
+    },
+    watch: {
+      files: ['./supermodel.js', 'test/**/*.js'],
+      tasks: ['tape'],
+    }
+  });
+  // Enable plugins
+  grunt.loadNpmTasks('grunt-tape');
+  grunt.loadNpmTasks('grunt-contrib-watch');
+  // register tasks
+  grunt.registerTask('test', ['tape']);
+  // default task
+  grunt.registerTask('default', ['test']);
+};
diff --git a/README.md b/README.md
index 1120c53..4e1a258 100644
--- a/README.md
+++ b/README.md
@@ -4,3 +4,14 @@ Please see [pathable.github.com/supermodel][supermodel] for documentation.
 
 [supermodel]: http://pathable.github.com/supermodel
 [ci]: https://ci.testling.com/pathable/supermodel
+
+
+## How to contribute
+
+* Fork this repository on GitHub
+* Make sure you have [npm installed](https://www.npmjs.org/)
+* Run `npm install` in the root directory
+* Run the test suite with `grunt test`
+* Write failing test
+* Fix the test
+* Submit a pull request
diff --git a/package.json b/package.json
index e58bb15..6904edd 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,10 @@
     "uglify-js": "~2.4.11",
     "tape": "~2.4.2",
     "browserify": "~3.23.1",
-    "faucet": "0.0.0"
+    "faucet": "0.0.0",
+    "grunt": "~0.4.5",
+    "grunt-tape": "0.0.2",
+    "grunt-contrib-watch": "~0.6.1"
   },
   "testling": {
     "files": "test/*.js",
diff --git a/test/has.js b/test/has.js
index fa3ae5f..75c90e7 100644
--- a/test/has.js
+++ b/test/has.js
@@ -316,6 +316,13 @@ test('Many is initialized only once.', function(t) {
   t.end();
 });
 
+test('has.One and has.Many should play nicly together', function(t) {
+  var user = User.create({id: 1});
+  var memberships = user.memberships().add({id: 1, user_id: 1})
+  t.is(user.memberships().length, 1);
+  t.end();
+});
+
 test('Source is removed after parsing.', function(t) {
   var user = User.create();
   user.parse({memberships: [{id: 1}, {id: 2, hidden: true}]});