Add backers and sponsors from Open Collective
Add backers and sponsors from Open Collective

Now your open collective backers and sponsors can to appear directly on your README. 
see how it'll look [here](https://github.com/apex/apex#backers)
[More info](https://github.com/opencollective/opencollective/wiki/Github-banner)
Also add badges on top.
AtomLinter/Linter,steelbrain/linter,atom-community/linter