diff --git a/f6d575b1776440e237974e3ad9f582508660e5bf b/b0c63d594edc6cffa57e65712d2210879b9abaad
index f6d575b..b0c63d5 100644
--- a/f6d575b1776440e237974e3ad9f582508660e5bf
+++ b/b0c63d594edc6cffa57e65712d2210879b9abaad
@@ -3,3 +3,6 @@
 /.php_cs
 /.php_cs.cache
 /.phpunit.result.cache
+/composer.lock
+.idea/
+

diff --git a/4aaccb065f5c9a7d06ff99ba49465cf757706ab9 b/a1e91bee8291c7ffa894b9726f420ecc707a1192
index 4aaccb0..a1e91be 100644
--- a/4aaccb065f5c9a7d06ff99ba49465cf757706ab9
+++ b/a1e91bee8291c7ffa894b9726f420ecc707a1192
@@ -77,7 +77,7 @@ class Registry implements ArrayAccess {
 	 * Offset to retrieve.
 	 * @see http://php.net/manual/en/arrayaccess.offsetget.php
 	 * @param string $offset
-	 * @return mixed can return all value types
+	 * @return mixed|null can return all value types or null if not found
 	 */
 	public function offsetGet($offset) {
 		$parts = explode('.', $offset);
@@ -85,7 +85,7 @@ class Registry implements ArrayAccess {

 		foreach ($parts as $sublevel) {
 			if (!isset($position[$sublevel])) {
-				return;
+				return null;
 			}
 			$position = $position[$sublevel];
 		}

diff --git a/d2ed559b8bce86fd64da6867e2b1c09baf1d77b1 b/05f3cf714848b6d3df6e0e5b7b2cb714c4e576d3
index d2ed559..05f3cf7 100644
--- a/d2ed559b8bce86fd64da6867e2b1c09baf1d77b1
+++ b/05f3cf714848b6d3df6e0e5b7b2cb714c4e576d3
@@ -9,8 +9,9 @@
  * @author  Matthias Lantsch <[email protected]>
  */

-namespace holonet\common;
+namespace holonet\common\di;

+use TypeError;
 use Psr\Container\ContainerInterface;

 /**
@@ -61,4 +62,34 @@ class Container implements ContainerInterface {
 			}
 		}
 	}
+
+	/**
+	 * Method used to set a dependency in this class.
+	 * If the given value is an object, it will get injected and saved under the key
+	 * If the given value is a string a class name is assumed and a new object will be created and automatically get injected.
+	 * @param string $id The key to save the dependency under
+	 * @param object|string $value The dependency to save
+	 * @param array ...$constructorArgs Arguments for the class instantiation
+	 */
+	public function set(string $id, $value, ...$constructorArgs): void {
+		if (is_string($value) && class_exists($value)) {
+			try {
+				$value = new $value(...$constructorArgs);
+			} catch (TypeError $e) {
+				throw new DependencyInjectionException(
+					"Cannot create dependency '{$id}' on Dependency Container: '{$e->getMessage()}'",
+					$e->getCode(), $e
+				);
+			}
+		}
+
+		if (!is_object($value)) {
+			throw new DependencyInjectionException(
+				"Cannot set dependency '{$id}' on Dependency Container, value must be object or class string"
+			);
+		}
+
+		$this->inject($value);
+		$this->dependencies[$id] = $value;
+	}
 }

<?php
/**
 * This file is part of the holonet common library
 * (c) Matthias Lantsch.
 *
 * Class file for the Dependency Injection DependencyInjectionException class
 *
 * @license http://opensource.org/licenses/gpl-license.php  GNU Public License
 * @author  Matthias Lantsch <[email protected]>
 */

namespace holonet\common\di;

use RuntimeException;
use Psr\Container\ContainerExceptionInterface;

/**
 * Dependency Injection general error exception conforming with PSR-11.
 */
class DependencyInjectionException extends RuntimeException implements ContainerExceptionInterface {
}

diff --git a/e42629de6b44c6d0c1215509d73de8eaddd7b029 b/981b6805f6b4b8c613c596d05937617dd49534d4
index e42629d..981b680 100644
--- a/e42629de6b44c6d0c1215509d73de8eaddd7b029
+++ b/981b6805f6b4b8c613c596d05937617dd49534d4
@@ -9,7 +9,7 @@
  * @author  Matthias Lantsch <[email protected]>
  */

-namespace holonet\common;
+namespace holonet\common\di;

 use RuntimeException;
 use Psr\Container\NotFoundExceptionInterface;