add year to YAML data

event.py

@@ -90,6 +90,10 @@ class Event( Index ):
     def set_slug( self, slug ):
         self.fields[ '$slug' ] = slug
 
+    def set_year( self, year ):
+        if not self.fields.get( 'year' ):
+            self.fields[ 'year' ] = year
+
     def set_published( self, published ):
         if not self.fields.get( '$date' ):
             self.fields[ '$date' ] = {}