diff --git a/README.md b/README.md
index 46f5bba..44d6695 100644
--- a/README.md
+++ b/README.md
@@ -11,15 +11,93 @@ Run [Composer](https://getcomposer.org) to install new package:
 
 > How to install Composer: https://getcomposer.org/download
 
-## Usage
+## Static methods
 
-This package contains a lot of static methods, so usage is not so complicated. Just run the static method who would you like to use. Example:
+This package contains a lot of class with static methods, so usage is not so complicated. Just run the static method who would you like to use. Example:
 
 ```php
 use Meritoo\Common\Utilities\Arrays;
 
-$firstElement = Arrays::getFirstElement(['lorem' 'ipsum']);
-// result: "lorem"
+$firstElement = Arrays::getFirstElement(['lorem', 'ipsum']);
+var_dump($firstElement); // string(5) "lorem"
+```
+
+## Base test case with common methods and data providers
+
+Located here: `Meritoo\Common\Test\Base\BaseTestCase`. Just extend the `BaseTestCase` class and use it like in `Meritoo\Common\Test\Utilities\DateTest` class:
+
+```php
+class DateTest extends BaseTestCase
+{
+    /**
+     * @param mixed $value Empty value, e.g. ""
+     * @dataProvider provideEmptyValue
+     */
+    public function testGetDateTimeEmptyValue($value)
+    {
+        self::assertFalse(Date::getDateTime($value));
+    }
+
+	(...)
+}
+```
+
+or in `Meritoo\Common\Test\Utilities\MimeTypesTest` class:
+
+```php
+class MimeTypesTest extends BaseTestCase
+{
+	(...)
+
+    /**
+     * @param bool $mimeType The mime type, e.g. "video/mpeg"
+     * @dataProvider provideBooleanValue
+     */
+    public function testGetExtensionBooleanMimeType($mimeType)
+    {
+        self::assertEquals('', MimeTypes::getExtension($mimeType));
+    }
+
+	(...)
+}
+```
+
+## Collection of elements
+
+Located here: `Meritoo\Common\Collection\Collection`. It's a set of some elements, e.g. objects. It's iterable and countable. Provides very useful methods. Some of them:
+- `getFirst()` - returns the first element in the collection
+- `getLast()` - returns the last element in the collection
+- `isEmpty()` - returns information if collection is empty
+- `add($element, $index = null)` - adds given element (at the end of collection)
+- `addMultiple($elements, $useIndexes = false)` - adds given elements (at the end of collection)
+- `prepend($element)` - prepends given element (adds given element at the beginning of collection)
+- `remove($element)` - removes given element
+
+Examples of usage below.
+
+#### An empty collection
+
+```php
+use Meritoo\Common\Collection\Collection;
+
+$emptyCollection = new Collection();
+var_dump($emptyCollection->isEmpty()); // bool(true)
+```
+
+#### Simple collection
+
+```php
+use Meritoo\Common\Collection\Collection;
+
+$elements = [
+    'lorem',
+    'ipsum',
+    123 => 'dolor',
+    345 => 'sit',
+];
+
+$simpleCollection = new Collection($elements);
+var_dump($simpleCollection->has('dolor')); // bool(true)
 ```
 
 Enjoy!
diff --git a/composer.json b/composer.json
index 3574333..95f17fd 100644
--- a/composer.json
+++ b/composer.json
@@ -2,7 +2,7 @@
     "name": "meritoo/common-library",
     "description": "Useful classes, methods, extensions etc.",
     "license": "MIT",
-    "version": "0.0.5",
+    "version": "0.0.6",
     "authors": [
         {
             "name": "Meritoo.pl",