diff options
| -rw-r--r-- | app/models/time_table_combination.rb | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/app/models/time_table_combination.rb b/app/models/time_table_combination.rb index 1fa497d73..783ef53ef 100644 --- a/app/models/time_table_combination.rb +++ b/app/models/time_table_combination.rb @@ -6,7 +6,7 @@ class TimeTableCombination attr_accessor :source_id, :combined_id, :operation validates_presence_of :source_id, :combined_id, :operation - validates_inclusion_of :operation, :in => %w( union intersection disjunction) + validates_inclusion_of :operation, :in => %w( union intersection disjunction), :allow_nil => true def clean self.source_id = nil |