add apispec swagger generation

api/extensions.py

@@ -1,6 +1,7 @@
 from flask_jwt_extended import JWTManager
 from flask_migrate import Migrate
 from flask_sqlalchemy import SQLAlchemy, Model
+from flask_apispec import FlaskApiSpec
 
 class CRUDMixin(Model):
     """Mixin that adds convenience methods for CRUD (create, read, update, delete) operations."""
@@ -32,3 +33,4 @@ class CRUDMixin(Model):
 db = SQLAlchemy(model_class=CRUDMixin)
 migrate = Migrate()
 jwt = JWTManager()
+apispec = FlaskApiSpec()