Build insert-user command too

Dockerfile

@@ -19,11 +19,15 @@ WORKDIR /app
 ## executable of our Go program
 RUN cd cmd/server \
 	&& go mod download go.cryptoscope.co/secretstream \
+	&& go build . \
+	&& cd ../insert-user \
 	&& go build .
 
 RUN apk del build-dependencies \
  && rm -rf /var/cache/apk/* /tmp/*
 
+VOLUME /app/data
+
 COPY entrypoint.sh /docker-entrypoint.sh
 
 ## Our start command which kicks off