refactored app structure

app/main/errors.py

@@ -0,0 +1,12 @@
+from flask import render_template
+from . import main
+
+
+
+@main.app_errorhandler(404)
+def not_found(e):
+    return render_template('404.html'), 404
+
+@main.errorhandler(500)
+def server_error(e):
+    return render_template('500.html'), 500