[Feature] Add Badges to README

[kindoflew]

next_rails is FastRuby's 2nd most starred project (after Skunk) so it would be nice to have badges in the README like the other projects do.

Before we start...:

• I checked the documentation and didn't find this feature
• I checked to make sure that this feature has not already been requested

Problem:

As a potential user of next_rails
I want to see relevant stats about the project
So that I can accurately assess if I'd like to use it

I will abide by the code of conduct