Add mandatory fields to assets

app/models/asset.rb

@@ -10,7 +10,7 @@ class Asset
   
   has_one :i18n_variable, :as => :language_value, :autosave => true, :dependent => :destroy
   
-  validates_presence_of :filename, :data
+  validates_presence_of :filename, :data, :asset_category_id
 
   belongs_to :asset_category
   belongs_to :assetable, polymorphic: true