Add public flag checking

docs/api.md

@@ -113,6 +113,13 @@ The following is an example of an object containing two `Model` definitions: "lo
 
 Define a `Model` and export it for use by remote clients.
 
+**definition**
+
+ - `public` - **default: true** attach the `Model` to the app and export its methods to clients
+ - `dataSource` - **required** the name of the `DataSource` to attach the `Model` to
+
+**Example**
+
 ```js
 // declare a DataSource
 app.boot({

lib/application.js

@@ -67,6 +67,7 @@ app.model = function (Model, config) {
     return;
   }
   var modelName = Model;
+  config = config || {};
   assert(typeof modelName === 'string', 'app.model(name, config) => "name" name must be a string');
 
   Model =
@@ -74,7 +75,9 @@ app.model = function (Model, config) {
   this.models[classify(modelName)] =
   this.models[camelize(modelName)] = modelFromConfig(modelName, config, this);
 
+  if(config.public !== false) {
     this.model(Model);
+  }
 
   return Model;
 }