Merge branch 'fj-refactor-snippet-model' into 'master'

Remove unnecessary relations and scopes in ProjectSnippet

See merge request gitlab-org/gitlab!19493

app/models/project_snippet.rb

@@ -2,13 +2,6 @@
 
 class ProjectSnippet < Snippet
   belongs_to :project
-  belongs_to :author, class_name: "User"
 
   validates :project, presence: true
-
-  # Scopes
-  scope :fresh, -> { order("created_at DESC") }
-
-  participant :author
-  participant :notes_with_associations
 end