updated README.md to use flask cli in examples

README.md

@@ -20,49 +20,42 @@ This is an example application that handles database migrations through Flask-Mi
 ```python
 from flask import Flask
 from flask_sqlalchemy import SQLAlchemy
-from flask_script import Manager
-from flask_migrate import Migrate, MigrateCommand
+from flask_migrate import Migrate
 
 app = Flask(__name__)
 app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///app.db'
 
 db = SQLAlchemy(app)
 migrate = Migrate(app, db)
 
-manager = Manager(app)
-manager.add_command('db', MigrateCommand)
-
 class User(db.Model):
     id = db.Column(db.Integer, primary_key=True)
     name = db.Column(db.String(128))
-
-if __name__ == '__main__':
-    manager.run()
 ```
 
 With the above application you can create the database or enable migrations if the database already exists with the following command:
 
-    $ python app.py db init
-    
-This will add a `migrations` folder to your application. The contents of this folder need to be added to version control along with your other source files. 
+    $ flask db init
+
+Note that the `FLASK_APP` environment variable must be set according to the Flask documentation for this command to work. This will add a `migrations` folder to your application. The contents of this folder need to be added to version control along with your other source files. 
 
 You can then generate an initial migration:
 
-    $ python app.py db migrate
+    $ flask db migrate
 
 The migration script needs to be reviewed and edited, as Alembic currently does not detect every change you make to your models. In particular, Alembic is currently unable to detect indexes. Once finalized, the migration script also needs to be added to version control.
 
 Then you can apply the migration to the database:
 
-    $ python app.py db upgrade
+    $ flask db upgrade
 
 Then each time the database models change repeat the `migrate` and `upgrade` commands.
 
 To sync the database in another system just refresh the `migrations` folder from source control and run the `upgrade` command.
 
 To see all the commands that are available run this command:
 
-    $ python app.py db --help
+    $ flask db --help
 
 Resources
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