[enhancement] Add timezone in to Dockerfile

[kis87988]

Right now, we can not declare a environment (ENV) varialbe to set timezone
My idea is:

1. apk add tzdata
2. set ENV localTime America/Los_Angeles
3. RUN cp /usr/share/zoneinfo/${localTime} /etc/localtime
   but I could not figure it out how to make it run in the dockerfile

The alternating method is:
create container first by docker pull/docker run and then docker enter to the container.
do the following:

1. apk add -U tzdata
2. cp /usr/share/zoneinfo/America/Los_Angeles /etc/localtime

Hope someone can make it into dockerfile.

[huan]

Thanks for purposing!

I believe setting timezone is a necessary feature that Wechaty Docker Image should support.

[huan]

Support to set TZ for timezone at Wechaty version 0.13.13 or above at: 61c277c

Usage:

docker run -e TZ='Asia/Shanghai' zixia/wechaty