Update README.md

README.md

@@ -8,13 +8,27 @@
 
 [![codecov.io](http://codecov.io/github/DotNetAnalyzers/PublicApiAnalyzer/coverage.svg?branch=master)](http://codecov.io/github/DotNetAnalyzers/PublicApiAnalyzer?branch=master)
 
+The purpose of this analyzer is to write the public API to two text files, **PublicAPI.Unshipped.txt** and **PublicAPI.Shipped.txt**. Add the files to source control to keep track of how the API evolves.
+
 ## Using Public API Analyzer
 
 The preferable way to use this package is to add the NuGet package [DotNetAnalyzers.PublicApiAnalyzer](http://www.nuget.org/packages/DotNetAnalyzers.PublicApiAnalyzer/)
 to the project where you want to enforce rules.
 
 The severity of individual rules may be configured using [rule set files](https://msdn.microsoft.com/en-us/library/dd264996.aspx)
-in Visual Studio 2015.
+in Visual Studio.
+
+### In development
+
+Use the code fix to update **PublicAPI.Unshipped.txt**.
+
+### When releasing
+
+1. Delete the contents of **PublicAPI.Unshipped.txt** and **PublicAPI.Shipped.txt**.
+2. Use the code fix to write the public API to **PublicAPI.Unshipped.txt**.
+3. Cut the contents of **PublicAPI.Unshipped.txt** and paste it to **PublicAPI.Shipped.txt**.
+
+The result should be empty **PublicAPI.Unshipped.txt** and complete **PublicAPI.Unshipped.txt**.
 
 ## Team Considerations