Endpoint for purging all objects in class (#2032)

* Endpoint for purging all objects in class

* Use deleteObjectsByQuery

* Standalone handling function and purge cache

* Change endpoint url

src/Controllers/DatabaseController.js

@@ -91,6 +91,16 @@ DatabaseController.prototype.collectionExists = function(className) {
   return this.adapter.classExists(className);
 };
 
+DatabaseController.prototype.purgeCollection = function(className) {
+  return this.loadSchema()
+  .then((schema) => {
+    schema.getOneSchema(className)
+  })
+  .then((schema) => {
+    this.adapter.deleteObjectsByQuery(className, {}, schema);
+  });
+};
+
 DatabaseController.prototype.validateClassName = function(className) {
   if (this.skipValidation) {
     return Promise.resolve();