VisualStudio ignore project.fragment.lock.json

I've just upgraded to ASP.NET Core RC2, and I've found that Visual
Studio is producing a file called project.fragment.lock.json. When I
delete the file it is recreated during build. Given project.lock.json is
already ignored this looks like another file to ignore.

VisualStudio.gitignore

@@ -42,6 +42,7 @@ dlldata.c
 
 # DNX
 project.lock.json
+project.fragment.lock.json
 artifacts/
 
 *_i.c