allow a caller to pass settings to make_app()

autoca/ca_app.py

@@ -92,9 +92,11 @@ def sign():
     return crypto.dump_certificate(crypto.FILETYPE_PEM, signed_cert)
 
 
-def make_app(ca_instance):
+def make_app(ca_instance, settings={}):
     app = Flask(__name__)
     app.register_blueprint(ca_app)
+    if settings:
+        app.config.update(settings)
     app.config.from_envvar('CA_APP_SETTINGS', silent=True)
     app.ca = ca_instance
     return app