Documentation and dockerfile cleanups

Dockerfile

@@ -1,6 +1,4 @@
 FROM python:3.6
-VOLUME /mapping
-
 LABEL MAINTAINER "Yuri Astrakhan <YuriAstrakhan@gmail.com>"
 
 WORKDIR /usr/src/app
@@ -12,9 +10,3 @@ RUN pip install --no-cache-dir -r requirements.txt
 COPY . /usr/src/app/
 
 ENTRYPOINT ["python", "server.py"]
-
-# Users can easily override prepared file with their own:
-#
-#   docker run -it --rm --net=host -v "$PWD:/mapping" openmaptiles/postserve /mapping/myfile.sql
-#
-CMD ["/mapping/mvt/maketile_prep.sql"]

README.md

@@ -1,2 +1,16 @@
 # postserve
-Use the ST_AsMVT function to render tiles directly in Postgres
+
+This is an OpenMapTiles map vector tile test server.  It requires the prepared SQL statement 
+generated by the `generate-sqltovmt` tools script.
+
+To run, use this command, replacing `myfile.sql` with the name of the generated file in the current dir.
+
+```
+docker run -it --rm --net=host -v "$PWD:/data" openmaptiles/postserve /data/myfile.sql
+```
+
+To see help, use
+
+```
+docker run -it --rm --net=host -v "$PWD:/data" openmaptiles/postserve --help
+```