transferred Code Ocean from original repository to GitHub

app/policies/code_ocean/file_policy.rb

@@ -0,0 +1,23 @@
+module CodeOcean
+  class FilePolicy < AdminOrAuthorPolicy
+    def author?
+      @user == @record.context.author
+    end
+
+    def create?
+      if @record.context.is_a?(Exercise)
+        admin? || author?
+      else
+        author?
+      end
+    end
+
+    def destroy?
+      if @record.context.is_a?(Exercise)
+        admin? || author?
+      else
+        no_one
+      end
+    end
+  end
+end