Update README.md

Author: Federico Moyá

README.md

@@ -1,3 +1,18 @@
 # JSON formatter for SimpleCov
 
-JSON formatter for the SimpleCov gem.
+***Note: To learn more about SimpleCov, check out the main repo at [https://github.com/simplecov-ruby/simplecov](https://github.com/colszowka/simplecov***)***
+
+Generates a formatted JSON report of your [SimpleCov](https://github.com/simplecov-ruby/simplecov) ruby code coverage results on ruby 2.4+.
+
+## Overview
+
+You can expect for this gem to produce a `coverage.json` file, located at the `coverage` folder. 
+
+Depending on your `SimpleCoV`'s settings you will experiment different outcomes. Particularly depending on which type of coverage are you running `SimpleCov` wit:
+
+- If you configure `SimpleCov` to run with `branch` coverage you should expect an output formatted like [sample_with_branch.json](https://github.com/fede-moya/simplecov_json_formatter/blob/master/spec/fixtures/sample_with_branch.json)
+- Otherwise you should expect an output formatted like [sample.json](https://github.com/fede-moya/simplecov_json_formatter/blob/master/spec/fixtures/sample.json)
+
+## Copyright
+
+See License ?