Updated README.md with badge and Nuget feed information.

README.md

@@ -1,2 +1,8 @@
-# githubjwt
-A helper library to generate GitHub JWT from GitHub Apps private key
+# GitHubJwt
+
+A helper library to generate GitHub JWT from GitHub Apps private key.
+
+[![Build status](https://ci.appveyor.com/api/projects/status/58svorf4e8ayx7pw/branch/master?svg=true)](https://ci.appveyor.com/project/adriangodong/githubjwt/branch/master)
+[![NuGet](https://img.shields.io/nuget/v/GitHubJwt.svg)](https://www.nuget.org/packages/GitHubJwt/)
+
+Pull Request Nuget artifacts are available from AppVeyor Project Nuget feed at `https://ci.appveyor.com/nuget/githubjwt`. To use a custom feed, please refer to the following [documentation](https://docs.microsoft.com/en-us/nuget/tools/package-manager-ui#package-sources).