Install tzdata and added instructions for setting the timezone via the TZ environment variable

Dockerfile

@@ -18,7 +18,7 @@ RUN chmod +x /usr/local/bin/supw
 ENV BZIP_URL https://github.com/mumble-voip/mumble/releases/download/${MUMBLE_VERSION}/murmur-static_x86-${MUMBLE_VERSION}.tar.bz2
 
 # Install dependencies and fetch Mumble bzip archive
-RUN apk add --update ca-certificates bzip2 tar wget \
+RUN apk add --update ca-certificates bzip2 tar tzdata wget \
     && wget -qO- ${BZIP_URL} | tar -xjv --strip-components=1 -C /opt/mumble \
     && apk del ca-certificates bzip2 tar wget && rm -rf /var/cache/apk/*
 

README.md

@@ -21,8 +21,14 @@ the data-only container:
 
 #### Optional 'docker run' arguments
 
-`--restart always` - Always restart the container regardless of the exit status. See the Docker
-                     [restart policies](https://goo.gl/OI87rA) for additional details.
+`-e TZ=America/Phoenix` - Set the timezone for your server. You can find your timezone in this
+                          [list of timezones](https://goo.gl/uy1J6q). Use the (case sensitive)
+                          value from the `TZ` column. If left unset, timezone will be UTC.
+
+`--restart unless-stopped` - Always restart the container regardless of the exit status, but do not
+                             start it on daemon startup if the container has been put to a stopped
+                             state before. See the Docker [restart policies](https://goo.gl/Y0dlDH)
+                             for additional details.
 
 Get/Set the SuperUser Password
 ------------------------------