added comments to dockerfiles

Dockerfile

@@ -1,10 +1,28 @@
 FROM python:2.7-alpine
 MAINTAINER Dan Feeney "feend78@gmail.com"
+
+# install compilation environment
 RUN apk update && apk add gcc musl-dev
+
+# add the project source
 ADD . /usr/src/evennia
+
+# install dependencies
 RUN pip install -e /usr/src/evennia
+
+# add the game source during game builds
 ONBUILD ADD . /usr/src/game
+
+# make the game source hierarchy persistent with a named volume.
+# during development this is typically superceded by directives in 
+# docker-compose.yml or the CLI to mount a local directory.
 VOLUME /usr/src/game
+
+# set the working directory
 WORKDIR /usr/src/game
-CMD ["evennia", "-l", "-i", "start"]
+
+# startup command
+CMD ["evennia", "-i", "start"]
+
+# expose the default ports
 EXPOSE 8000 8001 4000