Create observable commits client

Octokit.Reactive/Clients/IObservableCommitsClient.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Octokit.Reactive
+{
+    public interface IObservableCommitsClient
+    {
+        /// <summary>
+        /// Gets a commit for a given repository by sha reference
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/commits/#get-a-commit
+        /// </remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="reference">Tha sha reference of the commit</param>
+        /// <returns></returns>
+        [SuppressMessage("Microsoft.Naming", "CA1716:IdentifiersShouldNotMatchKeywords", MessageId = "Get",
+            Justification = "Method makes a network request")]
+        IObservable<Commit> Get(string owner, string name, string reference);        
+    }
+}