Changed modules to extensions

ref-test/app/extensions.py

@@ -0,0 +1,10 @@
+from flask_bootstrap import Bootstrap
+bootstrap = Bootstrap()
+from flask_wtf.csrf import CSRFProtect
+csrf = CSRFProtect()
+from flask_sqlalchemy import SQLAlchemy
+db = SQLAlchemy()
+from flask_login import LoginManager
+login_manager = LoginManager()
+from flask_mail import Mail
+mail = Mail()