add python notes

python.md

@@ -0,0 +1,25 @@
+---
+author: Alvie Rahman
+date: \today
+title: Python
+tags: [ docker, python, programming, io ]
+---
+
+# Issues
+
+## No log output when running in docker
+
+Change line beginning with `CMD` from:
+
+```Dockerfile
+CMD [ "python", "app.py" ]
+```
+
+to:
+
+```Dockerfile
+CMD [ "python", "-u", "app.py" ]
+```
+
+This disabled output buffering (stdout and stderr).
+