Add performance test for LeastSquares (#263)

* Install phpbench 🚀

* Add first benchmark for LeastSquares

* Update README and CONTRIBUTING guide

* Fix typo

.gitignore

@@ -1,3 +1,4 @@
 /vendor/
 .php_cs.cache
 /build
+/tests/Performance/Data/*.csv

CONTRIBUTING.md

@@ -8,36 +8,52 @@ code base clean, unified and future proof.
 
 You should only open pull requests against the `master` branch.
 
-## Unit-Tests
+## Unit Tests
 
 Please try to add a test for your pull-request. You can run the unit-tests by calling:
 
 ```bash
 vendor/bin/phpunit
 ```
 
+## Performance Tests
+
+Before first run bootstrap script will download all necessary datasets from public repository `php-ai/php-ml-datasets`.
+
+Time performance tests:
+
+```bash
+vendor/bin/phpbench run --report=time
+```
+
+Memory performance tests:
+
+```bash
+vendor/bin/phpbench run --report=memory
+```
+
 ## Travis
 
 GitHub automatically run your pull request through Travis CI.
 If you break the tests, I cannot merge your code, so please make sure that your code is working before opening up a Pull-Request.
 
 ## Merge
 
-Please allow me time to review your pull requests. I will give my best to review everything as fast as possible, but cannot always live up to my own expectations.
+Please give me time to review your pull requests. I will give my best to review everything as fast as possible, but cannot always live up to my own expectations.
 
 ## Coding Standards & Static Analysis
 
 When contributing code to PHP-ML, you must follow its coding standards. To do that, just run:
 
 ```bash
-vendor/bin/ecs check src tests --fix
+composer fix-cs
 ```
 [More about EasyCodingStandard](https://github.com/Symplify/EasyCodingStandard)
 
 Code has to also pass static analysis by [PHPStan](https://github.com/phpstan/phpstan):
 
 ```bash
-vendor/bin/phpstan.phar analyse src tests --level max --configuration phpstan.neon
+composer phpstan
 ```
 
 

README.md

@@ -9,11 +9,9 @@
 [![Coverage Status](https://coveralls.io/repos/github/php-ai/php-ml/badge.svg?branch=master)](https://coveralls.io/github/php-ai/php-ml?branch=master)
 [![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/php-ai/php-ml/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/php-ai/php-ml/?branch=master)
 
-<a href="http://www.yegor256.com/2016/10/23/award-2017.html">
-  <img src="http://www.yegor256.com/images/award/2017/winner-itcraftsmanpl.png"
-  style="width:203px;height:45px;"/></a>
-
-![PHP-ML - Machine Learning library for PHP](docs/assets/php-ml-logo.png)
+<p align="center">
+	<img src="https://github.com/php-ai/php-ml/blob/master/docs/assets/php-ml-logo.png" />
+</p>
 
 Fresh approach to Machine Learning in PHP. Algorithms, Cross Validation, Neural Network, Preprocessing, Feature Extraction and much more in one library.
 
@@ -35,6 +33,11 @@ echo $classifier->predict([3, 2]);
 // return 'b'
 ```
 
+## Awards
+
+<a href="http://www.yegor256.com/2016/10/23/award-2017.html">
+  <img src="http://www.yegor256.com/images/award/2017/winner-itcraftsmanpl.png" width="400"/></a>
+
 ## Documentation
 
 To find out how to use PHP-ML follow [Documentation](http://php-ml.readthedocs.org/).
@@ -51,6 +54,10 @@ composer require php-ai/php-ml
 
 Example scripts are available in a separate repository [php-ai/php-ml-examples](https://github.com/php-ai/php-ml-examples).
 
+## Datasets
+
+Public datasets are available in a separate repository [php-ai/php-ml-datasets](https://github.com/php-ai/php-ml-datasets).
+
 ## Features
 
 * Association rule learning
@@ -120,6 +127,7 @@ Example scripts are available in a separate repository [php-ai/php-ml-examples](
 
 ## Contribute
 
+- [Guide: CONTRIBUTING.md](https://github.com/php-ai/php-ml/blob/master/CONTRIBUTING.md)
 - [Issue Tracker: github.com/php-ai/php-ml](https://github.com/php-ai/php-ml/issues)
 - [Source Code:  github.com/php-ai/php-ml](https://github.com/php-ai/php-ml)
 

composer.json

@@ -23,6 +23,7 @@
         "php": "^7.1"
     },
     "require-dev": {
+        "phpbench/phpbench": "^0.14.0",
         "phpstan/phpstan-phpunit": "^0.9.4",
         "phpstan/phpstan-shim": "^0.9",
         "phpstan/phpstan-strict-rules": "^0.9.0",