Added contributing.md to the .sln

Author: robdmoore

TestStack.Dossier.sln

@@ -1,11 +1,12 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 2013
-VisualStudioVersion = 12.0.30723.0
+VisualStudioVersion = 12.0.31101.0
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{BC8508D1-6FCB-46B2-9C14-F41F6AD76B09}"
 	ProjectSection(SolutionItems) = preProject
 		BREAKING_CHANGES.md = BREAKING_CHANGES.md
+		CONTRIBUTING.md = CONTRIBUTING.md
 		LICENSE = LICENSE
 		logo.png = logo.png
 		NextVersion.txt = NextVersion.txt