adds a .scss for likebutton and definePlugin webpack

Previously there was a problem if we were to test a component that contains a require to a .scss file: jest would go crazy with the different require and fail the tests. With a plugin set for defining the process.env variable we are able to tackle this issue.
This commit also adds a .scss for a component so that we are able to fully validate this.
Merge pull request #8 from cirocosta/feat/plugin-node-env

(react) fix webpack requires messing w/ jest