Add new MongoSchemaCollection class that manages schemas for all collections.

src/Controllers/DatabaseController.js

@@ -33,6 +33,10 @@ DatabaseController.prototype.adaptiveCollection = function(className) {
   return this.adapter.adaptiveCollection(this.collectionPrefix + className);
 };
 
+DatabaseController.prototype.schemaCollection = function() {
+  return this.adapter.schemaCollection(this.collectionPrefix);
+};
+
 DatabaseController.prototype.collectionExists = function(className) {
   return this.adapter.collectionExists(this.collectionPrefix + className);
 };