Added README and CHANGELOG entries

CHANGELOG.md

@@ -3,3 +3,8 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/) and [Keep a CHANGELOG](http://keepachangelog.com).
 
+## 1.0.0 - 2016-08-29
+
+### Added
+
+* Interval validation in boolean and/or guarding manner

README.md

@@ -9,3 +9,67 @@
 
 A validator for crontab values
 
+## Features
+
+* Validation of crontab interval strings like <kbd>6,21,36,51 7-23/1 * FEB-NOV/2 *</kbd>.
+
+## Requirements
+
+* PHP >= 7.0.0
+
+## Usage
+
+### Boolean validation
+
+```php
+<?php declare(strict_types=1);
+
+namespace MyVendor\MyProject;
+
+use hollodotme\CrontabValidator\CrontabValidator;
+
+$validator = new CrontabValidator();
+if ( $validator->isIntervalValid('6,21,36,51 7-23/1 * FEB-NOV/2 *') )
+{
+	echo "Interval is valid.";
+}
+else
+{
+	echo "Interval is invalid.";	
+}
+```
+
+### Guarding
+
+```php
+<?php declare(strict_types=1);
+
+namespace MyVendor\MyProject;
+
+use hollodotme\CrontabValidator\CrontabValidator;
+use hollodotme\CrontabValidator\Exceptions\InvalidCrontabInterval;
+
+$validator = new CrontabValidator();
+
+try 
+{
+	# => All fine, execution continues
+	$validator->guardIntervalIsValid('6,21,36,51 7-23/1 * FEB-NOV/2 *');
+
+	# => This will raise an InvalidCrontabInterval exception
+	$validator->guardIntervalIsValid('this is not a valid interval');
+}
+catch (InvalidCrontabInterval $e)
+{
+	echo $e->getMessage() . ': "' . $e->getCrontabInterval() . '"';
+}
+```
+
+**Prints:**
+
+	Invalid crontab interval: "this is not a valid interval"
+
+
+---
+
+Feedback and contributions welcome!