Update README.md (Michannne#16)

Added travis-CI support

Author: Michannne

README.md

@@ -1,7 +1,7 @@
 # graphql-core
 A wrapper library for GraphQL.NET that provides additional features to ease enterprise integration
 
-[![Build status](https://ci.appveyor.com/api/projects/status/dptn1yq8wc65mmxs?svg=true)](https://ci.appveyor.com/project/Michannne/graphql-core) [![Nuget](https://img.shields.io/nuget/v/GraphQL-Core.svg)](https://www.nuget.org/packages/GraphQL-Core)
+[![Build status](https://ci.appveyor.com/api/projects/status/dptn1yq8wc65mmxs?svg=true)](https://ci.appveyor.com/project/Michannne/graphql-core) [![Nuget](https://img.shields.io/nuget/v/GraphQL-Core.svg)](https://www.nuget.org/packages/GraphQL-Core) [![Travis (.org)](https://img.shields.io/travis/Michannne/GraphQL-Core.svg?label=travis-CI&logo=travis)](https://travis-ci.org/Michannne/graphql-core)
 
 GraphQL.NET can be found [here](https://github.com/graphql-dotnet/graphql-dotnet/)