Looks like this is late but FYI, it looks like it should go in the Models folder, not in the controller.
On the MVC Music Store tutorial, I found this part that indicates that the Models folder is the correct place.
"Adding our store catalog data
We will take advantage of a feature in Entity Framework which adds “seed” data to a newly created database. This will pre-populate our store catalog with a list of Genres, Artists, and Albums. The MvcMusicStore-Assets.zip download - which included our site design files used earlier in this tutorial - has a class file with this seed data, located in a folder named Code.
Within the Code / Models folder, locate the SampleData.cs file and drop it into the Models folder in our project, as shown below."