added opt-in header for passing Context to API

Octokit/Clients/CommitStatusClient.cs

@@ -34,7 +34,12 @@ namespace Octokit
             Ensure.ArgumentNotNullOrEmptyString(name, "name");
             Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
 
-            return ApiConnection.GetAll<CommitStatus>(ApiUrls.CommitStatus(owner, name, reference), null);
+            // This is currently a preview feature of the API and is subject to change
+            // https://developer.github.com/v3/repos/statuses/#list-statuses-for-a-specific-ref
+            return ApiConnection.GetAll<CommitStatus>(
+                ApiUrls.CommitStatus(owner, name, reference),
+                null,
+                "application/vnd.github.she-hulk-preview+json");
         }
 
         /// <summary>
@@ -52,7 +57,12 @@ namespace Octokit
             Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
             Ensure.ArgumentNotNull(commitStatus, "commitStatus");
 
-            return ApiConnection.Post<CommitStatus>(ApiUrls.CommitStatus(owner, name, reference), commitStatus);
+            // This is currently a preview feature of the API and is subject to change
+            // https://developer.github.com/v3/repos/statuses/#list-statuses-for-a-specific-ref
+            return ApiConnection.Post<CommitStatus>(
+                ApiUrls.CommitStatus(owner, name, reference),
+                commitStatus,
+                "application/vnd.github.she-hulk-preview+json");
         }
     }
 }

Octokit/Models/Response/CommitStatus.cs

@@ -33,6 +33,11 @@ namespace Octokit
         /// </summary>
         public string Description { get; set; }
 
+        /// <summary>
+        /// A string label to differentiate this status from the status of other systems.
+        /// </summary>
+        public string Context { get; set; }
+
         /// <summary>
         /// The unique identifier of the status.
         /// </summary>