move whether to debug or not into config file

zesje.dev.cfg

 BASIC_AUTH_USERNAME = 'test'
 BASIC_AUTH_PASSWORD = 'zesje'
 BASIC_AUTH_FORCE = 'True'
+FLASK_DEBUG = 1

zesje/__main__.py

@@ -3,4 +3,4 @@ import os
 sys.path.append(os.getcwd())
 
 from zesje import app
-app.run(debug=True)
+app.run()