extract OVERVIEW.md document which introduces the overall Octokit cod…

…ebase

CONTRIBUTING.md

@@ -25,40 +25,7 @@ easiest way to do this. You can then clone down your fork instead:
 After doing that, run the `.\build.cmd` script at the root of the repository 
 to ensure all the tests pass.
 
-### How is the codebase organised?
-
-The two main projects are the `Octokit` and `Octokit.Reactive` projects.
-
-The `Octokit.Reactive` library is a thin wrapper over the `Octokit` 
-library - for those who want to use Reactive Extensions (Rx) instead of tasks.
-
-The namespaces are organised so that the relevant components are easy to discover:
-
- - **Authentication** - everything related to authenticating requests 
- - **Clients** - the logic for interacting with various parts of the GitHub API
- - **Exceptions** - types which represent exceptional behaviour from the API 
- - **Helpers** - assorted extensions and helpers to keep the code neat and tidy
- - **Http** - the internal networking components which Octokit requires
- - **Models** - types which represent request/response objects
-
-Unless you're modifying some core behaviour, the **Clients** and **Models** namespaces
-are likely to be the most interesting areas.
-
-The clients within a project are organized similarly to the endpoints in the
-[GitHub API documentation](http://developer.github.com/v3/)
-
-Some clients are "sub-clients". For example, when you navigate to the
-[Issues API](http://developer.github.com/v3/issues/) you'll notice there's an
-endpoint for issues. But in the right navbar, there are other APIs such as
-[Assignees](http://developer.github.com/v3/issues/assignees/) and
-[Milestones](http://developer.github.com/v3/issues/milestones/).
-
-We've tried to mirror this structure. So the `IObservableMilestoneClient` isn't
-a direct property of `IObservableGitHubClient`. Instead, it's a property of the
-`IObservableIssuesClient`. And thus you can get to it by going to
-`client.Issues.Milestones`.
-
-### What needs to be done?
+### How can I get involved?
 
 We have a [`easy-fix`](https://github.com/octokit/octokit.net/issues?labels=easy-fix&state=open)
 tag on our issue tracker to indicate tasks which contributors can pick up.
@@ -141,4 +108,5 @@ Some things that will increase the chance that your pull request is accepted.
 
 # Additional Resources
 
+* [Octokit Codebase Overview](https://github.com/octokit/octokit.net/blob/master/OVERVIEW.md)
 * [General GitHub documentation](http://help.github.com/)

OVERVIEW.md

@@ -0,0 +1,32 @@
+### How is the codebase organised?
+
+The two main projects are the `Octokit` and `Octokit.Reactive` projects.
+
+The `Octokit.Reactive` library is a thin wrapper over the `Octokit`
+library - for those who want to use Reactive Extensions (Rx) instead of tasks.
+
+The namespaces are organised so that the relevant components are easy to discover:
+
+ - **Authentication** - everything related to authenticating requests
+ - **Clients** - the logic for interacting with various parts of the GitHub API
+ - **Exceptions** - types which represent exceptional behaviour from the API
+ - **Helpers** - assorted extensions and helpers to keep the code neat and tidy
+ - **Http** - the internal networking components which Octokit requires
+ - **Models** - types which represent request/response objects
+
+Unless you're modifying some core behaviour, the **Clients** and **Models** namespaces
+are likely to be the most interesting areas.
+
+The clients within a project are organized similarly to the endpoints in the
+[GitHub API documentation](http://developer.github.com/v3/)
+
+Some clients are "sub-clients". For example, when you navigate to the
+[Issues API](http://developer.github.com/v3/issues/) you'll notice there's an
+endpoint for issues. But in the right navbar, there are other APIs such as
+[Assignees](http://developer.github.com/v3/issues/assignees/) and
+[Milestones](http://developer.github.com/v3/issues/milestones/).
+
+We've tried to mirror this structure. So the `IObservableMilestoneClient` isn't
+a direct property of `IObservableGitHubClient`. Instead, it's a property of the
+`IObservableIssuesClient`. And thus you can get to it by going to
+`client.Issues.Milestones`.