Implement CI on this template

[tsaoyu]

Having continuous integration on this template allow us to test the template on different operating systems. The idea is to setup and running a Travis CI (linux, mac) and an Appveyor (windows) to compile tex files. Result pdf will then push back to result branch of this repo. We will able to tell if it works on different operating systems without having a local machine. Steps are

• Write a .travis.yml file to automatic build pdf on linux
• Send your pull request to me
• If your pull request makes sense to me, I will make you as a collaborator and you will have write access to this repo
• Extend .travis.yml to push the result pdf back to the repo
• Make it work on mac and/or windows

As a helper, you will:

• Learn something about git and how to contribute to an open source project
• Learn something about CI
• Having your name listed as a contributor in the template

[moooyo]

We can use GitHub Actions now.

[tsaoyu]

@moooyo Sure, I am happy to use different CI service as long as it fulfils the requirement.