Added codeowners and contributors.md

Author: Andrew Stewart Gibson

CODEOWNERS

@@ -0,0 +1 @@
+* @asbjornu @goofballlogic

contributors.md

@@ -0,0 +1,21 @@
+# Contributors and maintainers
+
+We maintain this list as a way to track who's currently involved in the project.
+Please use PRs to this document to propose adding new maintainers /
+contributors.
+
+[![Contributors](https://contributors-img.web.app/image?repo=linked-data-dotnet/json-ld.net)](https://github.com/linked-data-dotnet/json-ld.net/graphs/contributors)
+
+Made with [contributors-img](https://contributors-img.web.app).
+
+**N.B.** please propose names ordered alphabetically by username.
+
+## Admins
+
+ - [Asbjørn Ulsberg](https://github.com/asbjornu )
+ - [Andrew Stewart Gibson](https://github.com/goofballLogic)
+ 
+## Contributors
+
+ - [Tomasz Pluskiewicz](https://github.com/tpluscode)
+ - [Ben Abelshausen](https://github.com/xivk)