Set better theme (#14)

Cleaner, nicer:
![image](https://user-images.githubusercontent.com/183673/49167525-d492b200-f335-11e8-9860-f3884c39d992.png)
1 file changed
tree: 2e17a0ff04ebae841cc478d7e80f00775ce809d4
  1. README.md
  2. _config.yml