update CONTRIBUTING.md

CONTRIBUTING.md

@@ -2,18 +2,18 @@
 
 ## Pull Requests
 
-1. Fork this repository
-2. Create a new branch for each feature or improvement
-3. Send a pull request from each feature branch
+1. Fork this repository.
+2. Create a new branch for each feature or improvement.
+3. Send a pull request from each feature branch.
 
 It is very important to separate new features or improvements into separate feature branches, and to send a pull request for each branch. This allows me to review and pull in new features or improvements individually.
 
 ## Style Guide
 
-All pull requests must adhere to the [PSR-2 standard](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-2-coding-style-guide.md).
+All pull requests must adhere to the [PSR-12 standard](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-12-extended-coding-style-guide.md).
 
 ## Unit Testing
 
-All pull requests must be accompanied by passing unit tests and complete code coverage. The Slim Framework uses phpunit for testing.
+All pull requests must be accompanied by passing unit tests and complete code coverage. The Slim Framework uses PHPUnit for testing.
 
 [Learn about PHPUnit](https://github.com/sebastianbergmann/phpunit/)