Fix a small code typo in the Readme
Fix a small code typo in the Readme

I’m new to microstates and was just reading over the readme. I _think_ there is a small bug in the Array Microstates example.

The example creates a new `blog2` after immutably ‘pushing’ onto `blog.posts` but then logs out the values of `blog.posts` which wouldn’t have the newly pushed on value since `blog.posts` is immutable. I think the example should be logging out the new `blog2.posts`.
cowboyd/microstates.js