Dockerfile: add default Entrypoint and mount data dir

Closes #170
Closes #78

Thanks @ay-b

Author: nhooyr

Dockerfile

@@ -28,5 +28,6 @@ RUN apt-get install -y locales && \
 # We unfortunately cannot use update-locale because docker will not use the env variables
 # configured in /etc/default/locale so we need to set it manually.
 ENV LANG=en_US.UTF-8
-# Unfortunately `.` does not work with code-server.
+ENTRYPOINT code-server
+# Unfortunately `.` does not work with code-server so we use shell form.
 CMD code-server $PWD

README.md

@@ -9,7 +9,7 @@
 
 Try it out:
 ```bash
-docker run -p 127.0.0.1:8443:8443 -v "${PWD}:/root/project" codercom/code-server code-server --allow-http --no-auth
+docker run -p 127.0.0.1:8443:8443 -v "${PWD}:/root/project" -v ~/.code-server:/root/.code-server codercom/code-server --allow-http --no-auth
 ```
 
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