Added readme

Author: Alaa Sarhan

README.md

@@ -0,0 +1,85 @@
+# php-flatten
+
+A utility function to mainly flatten multidimensional-arrays and traversables into a one-dimensional array, preserving keys
+and joining them with a customizable separator to from fully-qualified keys in the final array.
+
+## Installation
+
+```
+  composer require sarhan/php-flatten
+```
+
+## Examples
+
+```php
+use Sarhan\Flatten;
+
+$multiArray = [
+    'say' => 'what',
+    'hi' => [ 'de' => 'Hallo', 'es' => 'Hola' ]
+];
+
+$array = Flatten::flatten($multiArray);
+
+/* print_r($array) gives:
+
+  Array
+  (
+      [say] => what
+      [hi.de] => Hallo
+      [hi.es] => Hola
+  )
+*/
+```
+
+Custom Separator and initial prefix
+```php
+use Sarhan\Flatten;
+
+$allowAccess = [
+    'root' => false,
+    'var' => [ 'log' => ['nginx' => true, 'apt' => false], 'www' => true ],
+];
+
+$allowAccess = Flatten::flatten($allowAccess, '/', '/');
+
+/* var_dump($array) gives:
+
+  array(4) {
+    '/root' =>
+    bool(false)
+    '/var/log/nginx' =>
+    bool(true)
+    '/var/log/apt' =>
+    bool(false)
+    '/var/www' =>
+    bool(true)
+  }
+*/
+```
+
+Notice that the prefix will not be separated in FQkeys. If it should be separated, separator must be appeneded to the prefix string.
+```php
+use Sarhan\Flatten;
+
+$api = [
+    'category' => [ 'health' => 321, 'sport' => 769, 'fashion' => 888 ],
+    'tag' => [ 'soccer' => 7124, 'tennis' => [ 'singles' => 9833, 'doubles' => 27127 ] ],
+];
+
+$uris = Flatten::flatten($api, '/', 'https://api.dummyhost.domain/');
+
+/* print_r($uris) gives:
+
+  Array
+  (
+      [https://api.dummyhost.domain/category/health] => 321
+      [https://api.dummyhost.domain/category/sport] => 769
+      [https://api.dummyhost.domain/category/fashion] => 888
+      [https://api.dummyhost.domain/tag/soccer] => 7124
+      [https://api.dummyhost.domain/tag/tennis/singles] => 9833
+      [https://api.dummyhost.domain/tag/tennis/doubles] => 27127
+  )
+
+*/
+```