Basic community stuff

[majormoses]

Basically a list of things that we need to update after transferring to the community:

• [x] terraform setup
• [x] travis-ci
• [x] rubygems.org
• [x] badges
• [x] standard changelog
• [x] standard rakefile
• [x] standard readme
• [x] standard gemspec
• [x] standard PR template
• [x] slack hook