Adding GitHubFlow major release docs and test

Author: JakeGinnivan

docs/git-branching-strategies/githubflow-examples.md

@@ -1,7 +1,12 @@
 # GitHubFlow Examples
 
 ## Feature branch
-![GitFlow](img/githubflow_feature-branch.png)
+![GitHubFlow](img/githubflow_feature-branch.png)
 
 ## Pull requests
-![GitFlow](img/githubflow_pull-request.png)
+![GitHubFlow](img/githubflow_pull-request.png)
+
+## Release branch
+Release branches can be used in GitHubFlow as well as GitFlow. Sometimes you want to start on a large feature which may take a while to stabilise so you want to keep it off master. In these scenarios you can either create a long lived feature branch (if you do not know the version number this large feature will go into, and it's non-breaking) otherwise you can create a release branch for the next major version. You can then submit pull requests to the long lived feature branch or the release branch.
+
+![GitFlow](img/githubflow_release-branch.png)

docs/git-branching-strategies/img/githubflow_release-branch.png

@@ -367,4 +367,45 @@ public void GitHubFlowPullRequestBranch()
             fixture.AssertFullSemver("1.2.1+3");
         }
     }
+
+    [Test]
+    public void GitHubFlowMajorRelease()
+    {
+        using (var fixture = new EmptyRepositoryFixture(new Config()))
+        {
+            fixture.Participant("master");
+
+            fixture.Repository.MakeACommit();
+            fixture.ApplyTag("1.3.0");
+
+            // Create release branch
+            fixture.BranchTo("release/2.0.0", "release");
+            fixture.Activate("release/2.0.0");
+            fixture.MakeACommit();
+            fixture.AssertFullSemver("2.0.0-beta.1+1");
+            fixture.MakeACommit();
+            fixture.AssertFullSemver("2.0.0-beta.1+2");
+
+            // Apply beta.1 tag should be exact tag
+            fixture.ApplyTag("2.0.0-beta.1");
+            fixture.AssertFullSemver("2.0.0-beta.1");
+
+            // Make a commit after a tag should bump up the beta
+            fixture.MakeACommit();
+            fixture.AssertFullSemver("2.0.0-beta.2+1");
+
+            // Complete release
+            fixture.Checkout("master");
+            fixture.MergeNoFF("release/2.0.0");
+            fixture.Destroy("release/2.0.0");
+            fixture.NoteOver("Release branches are deleted once merged", "release/2.0.0");
+            
+            fixture.AssertFullSemver("2.0.0+0");
+            fixture.ApplyTag("2.0.0");
+            fixture.AssertFullSemver("2.0.0");
+            fixture.MakeACommit();
+            fixture.Repository.DumpGraph();
+            fixture.AssertFullSemver("2.0.1+1");
+        }
+    }
 }