Add Reactive versions of organization API and unit/integration tests

Octokit.Reactive/Clients/Enterprise/IObservableEnterpriseOrganizationClient.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Reactive.Threading.Tasks;
+
+namespace Octokit.Reactive
+{
+    /// <summary>
+    /// A client for GitHub's Enterprise Organization API
+    /// </summary>
+    /// <remarks>
+    /// See the <a href="https://developer.github.com/v3/enterprise/orgs/">Enterprise Organization API documentation</a> for more information.
+    ///</remarks>
+    public interface IObservableEnterpriseOrganizationClient
+    {
+        /// <summary>
+        /// Creates an Organization on a GitHub Enterprise appliance (must be Site Admin user).
+        /// </summary>
+        /// <remarks>
+        /// https://developer.github.com/v3/enterprise/orgs/#create-an-organization
+        /// </remarks>
+        /// <param name="newOrganization">A <see cref="NewOrganization"/> instance describing the organization to be created</param>
+        /// <returns>The <see cref="Organization"/> created.</returns>
+        IObservable<Organization> Create(NewOrganization newOrganization);
+    }
+}
+