Added basic, untested Dockerfile

This will be the basis for the docker support. I haven't
gotten it working yet as I need to make some other changes to
the script. Should this be kept as a separate branch...?

Dockerfile

@@ -0,0 +1,10 @@
+FROM python:3.13.2-alpine3.21
+
+WORKDIR /usr/src/app
+
+COPY discorss.py ./
+COPY discorss.conf /etc/
+
+RUN pip install --no-cache-dir requests feedparser
+
+CMD [ "python", "discorss.py" ]

discorss.py

@@ -210,4 +210,12 @@ def main():
 
 
 if __name__ == "__main__":
-    main()
+    if os.environ["INVOCATION_ID"]:
+        main()
+    else:
+        try:
+            while True:
+                main()
+                time.sleep(15 * 60)
+        except KeyboardInterrupt:
+            exit(0)