typo

Author: yegor256

README.md

@@ -35,7 +35,7 @@ If you want to add yours, join our
 ## How to contribute
 
 Read [these guidelines](https://www.yegor256.com/2014/04/15/github-guidelines.html).
-Make sure you build is green before you contribute
+Make sure your build is green before you contribute
 your pull request. You will need to have [Ruby](https://www.ruby-lang.org/en/) 2.3+,
 Java 8+, Maven 3.2+, PostgreSQL 10+, and
 [Bundler](https://bundler.io/) installed. Then: