Add explicit License file

Author: OkGoDoIt

LICENSE.md

@@ -0,0 +1,5 @@
+[![CC-0 Public Domain](https://licensebuttons.net/p/zero/1.0/88x31.png)](http://creativecommons.org/publicdomain/zero/1.0/)
+
+*To the extent possible under law, Roger Pincombe and all other contributors have waived all copyright and related or neighboring rights to OpenAI-API-dotnet. This work is published from: United States.*
+
+This library is licensed CC-0, in the public domain.  You can use it for whatever you want, publicly or privately, without worrying about permission or licensing or whatever.  It's just a wrapper around the OpenAI API, so you still need to get access to OpenAI from them directly.  I am not affiliated with OpenAI and this library is not endorsed by them, I just have beta access and wanted to make a C# library to access it more easily.  Hopefully others find this useful as well.  Feel free to open a PR if there's anything you want to contribute.

OpenAI_API.sln

@@ -9,6 +9,7 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "OpenAI_Tests", "OpenAI_Test
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{1B37C1A8-1122-49FD-A3C1-C8F697714C1B}"
 	ProjectSection(SolutionItems) = preProject
+		LICENSE.md = LICENSE.md
 		README.md = README.md
 	EndProjectSection
 EndProject