diff --git a/app.py b/app.py
deleted file mode 100755
index d7bc2c4..0000000
--- a/app.py
+++ /dev/null
@@ -1,4 +0,0 @@
-from src import app
-
-if __name__ == "__main__":
-    app.run()
diff --git a/debug.sh b/debug.sh
index e0dc617..34121d8 100755
--- a/debug.sh
+++ b/debug.sh
@@ -1,3 +1,7 @@
 #!/bin/sh
 
-venv/bin/python -m flask run --debug -h 192.168.5.3
+venv/bin/python -m flask \
+    --app src \
+    run \
+        --debug \
+        -h 192.168.5.3
diff --git a/src/__init__.py b/src/__init__.py
index 6784035..14aa9e6 100644
--- a/src/__init__.py
+++ b/src/__init__.py
@@ -8,20 +8,18 @@ from pygments import formatters, highlight, lexers
 import markdown
 
 from src import (
-    # tango_controller,
     utils,
     config,
 )
 
+# TODO: Put the creation of the Flask application into a function
+#       https://flask.palletsprojects.com/en/3.0.x/tutorial/factory/
+#       def create_app() -> flask.Flask:
 app = Flask(
     __name__,
     template_folder="../templates",
     static_folder="../static",
 )
-# app.register_blueprint(tango_controller.bp)
-
-# Edit
-# Create file
 
 
 def get_tree() -> dict:
diff --git a/src/utils.py b/src/utils.py
new file mode 100644
index 0000000..ae594fe
--- /dev/null
+++ b/src/utils.py
@@ -0,0 +1,9 @@
+# ERRORS ######################################################################
+
+def err(message: str, code: int):
+    return {"error": message}, code
+
+
+ERR_500 = err("Internal server error", 500)
+ERR_403 = err("Not authorized", 403)
+ERR_404 = err("Not found", 404)