Add new fields to NewRepository request and update RepositoriesClient…

….Create() method to specify preview accepts header and fix impacted unit tests

Octokit.Tests/Clients/RepositoriesClientTests.cs

@@ -40,7 +40,7 @@ public void UsesTheUserReposUrl()
 
                 client.Create(new NewRepository("aName"));
 
-                connection.Received().Post<Repository>(Arg.Is<Uri>(u => u.ToString() == "user/repos"), Arg.Any<NewRepository>());
+                connection.Received().Post<Repository>(Arg.Is<Uri>(u => u.ToString() == "user/repos"), Arg.Any<NewRepository>(), "application/vnd.github.polaris-preview+json");
             }
 
             [Fact]
@@ -52,7 +52,7 @@ public void TheNewRepositoryDescription()
 
                 client.Create(newRepository);
 
-                connection.Received().Post<Repository>(Args.Uri, newRepository);
+                connection.Received().Post<Repository>(Args.Uri, newRepository, "application/vnd.github.polaris-preview+json");
             }
 
             [Fact]
@@ -68,7 +68,7 @@ public async Task ThrowsRepositoryExistsExceptionWhenRepositoryExistsForCurrentU
                 var connection = Substitute.For<IApiConnection>();
                 connection.Connection.BaseAddress.Returns(GitHubClient.GitHubApiUrl);
                 connection.Connection.Credentials.Returns(credentials);
-                connection.Post<Repository>(Args.Uri, newRepository)
+                connection.Post<Repository>(Args.Uri, newRepository, "application/vnd.github.polaris-preview+json")
                     .Returns<Task<Repository>>(_ => { throw new ApiValidationException(response); });
                 var client = new RepositoriesClient(connection);
 
@@ -95,7 +95,7 @@ public async Task ThrowsExceptionWhenPrivateRepositoryQuotaExceeded()
                 var connection = Substitute.For<IApiConnection>();
                 connection.Connection.BaseAddress.Returns(GitHubClient.GitHubApiUrl);
                 connection.Connection.Credentials.Returns(credentials);
-                connection.Post<Repository>(Args.Uri, newRepository)
+                connection.Post<Repository>(Args.Uri, newRepository, "application/vnd.github.polaris-preview+json")
                     .Returns<Task<Repository>>(_ => { throw new ApiValidationException(response); });
                 var client = new RepositoriesClient(connection);
 
@@ -127,7 +127,8 @@ public async Task UsesTheOrganizationsReposUrl()
 
                 connection.Received().Post<Repository>(
                     Arg.Is<Uri>(u => u.ToString() == "orgs/theLogin/repos"),
-                    Args.NewRepository);
+                    Args.NewRepository,
+                    "application/vnd.github.polaris-preview+json");
             }
 
             [Fact]
@@ -139,7 +140,7 @@ public async Task TheNewRepositoryDescription()
 
                 await client.Create("aLogin", newRepository);
 
-                connection.Received().Post<Repository>(Args.Uri, newRepository);
+                connection.Received().Post<Repository>(Args.Uri, newRepository, "application/vnd.github.polaris-preview+json");
             }
 
             [Fact]
@@ -153,7 +154,7 @@ public async Task ThrowsRepositoryExistsExceptionWhenRepositoryExistsForSpecifie
                     + @"""code"":""custom"",""field"":""name"",""message"":""name already exists on this account""}]}");
                 var connection = Substitute.For<IApiConnection>();
                 connection.Connection.BaseAddress.Returns(GitHubClient.GitHubApiUrl);
-                connection.Post<Repository>(Args.Uri, newRepository)
+                connection.Post<Repository>(Args.Uri, newRepository, "application/vnd.github.polaris-preview+json")
                     .Returns<Task<Repository>>(_ => { throw new ApiValidationException(response); });
                 var client = new RepositoriesClient(connection);
 
@@ -178,7 +179,7 @@ public async Task ThrowsValidationException()
                     + @"""http://developer.github.com/v3/repos/#create"",""errors"":[]}");
                 var connection = Substitute.For<IApiConnection>();
                 connection.Connection.BaseAddress.Returns(GitHubClient.GitHubApiUrl);
-                connection.Post<Repository>(Args.Uri, newRepository)
+                connection.Post<Repository>(Args.Uri, newRepository, "application/vnd.github.polaris-preview+json")
                     .Returns<Task<Repository>>(_ => { throw new ApiValidationException(response); });
                 var client = new RepositoriesClient(connection);
 
@@ -199,7 +200,7 @@ public async Task ThrowsRepositoryExistsExceptionForEnterpriseInstance()
                     + @"""code"":""custom"",""field"":""name"",""message"":""name already exists on this account""}]}");
                 var connection = Substitute.For<IApiConnection>();
                 connection.Connection.BaseAddress.Returns(new Uri("https://example.com"));
-                connection.Post<Repository>(Args.Uri, newRepository)
+                connection.Post<Repository>(Args.Uri, newRepository, "application/vnd.github.polaris-preview+json")
                     .Returns<Task<Repository>>(_ => { throw new ApiValidationException(response); });
                 var client = new RepositoriesClient(connection);
 

Octokit/Clients/RepositoriesClient.cs

@@ -82,7 +82,7 @@ async Task<Repository> Create(Uri url, string organizationLogin, NewRepository n
         {
             try
             {
-                return await ApiConnection.Post<Repository>(url, newRepository).ConfigureAwait(false);
+                return await ApiConnection.Post<Repository>(url, newRepository, AcceptHeaders.SquashCommitPreview).ConfigureAwait(false);
             }
             catch (ApiValidationException e)
             {

Octokit/Models/Request/NewRepository.cs

@@ -82,6 +82,21 @@ public NewRepository(string name)
         /// </summary>
         public int? TeamId { get; set; }
 
+        /// <summary>
+        /// Optional. Allows the "Rebase and Merge" method to be used.
+        /// </summary>
+        public bool? AllowRebaseMerge { get; set; }
+
+        /// <summary>
+        /// Optional. Allows the "Squash Merge" merge method to be used.
+        /// </summary>
+        public bool? AllowSquashMerge { get; set; }
+
+        /// <summary>
+        /// Optional. Allows the "Create a merge commit" merge method to be used.
+        /// </summary>
+        public bool? AllowMergeCommit { get; set; }
+
         internal string DebuggerDisplay
         {
             get