Fix User.login credentials check and flush Redis before tests

nodejs/test_table_del.js

@@ -0,0 +1,9 @@
+const {setUpTable} = require('model-redis');
+const redis = require('redis');
+const client = redis.createClient();
+const Table = setUpTable(client, 'prefix_');
+Table._keyMap = { token: { type: 'string' } };
+Table._key = 'token';
+Table.register(Table);
+const inst = new Table({token: '123'});
+console.log(typeof inst.del);