Validate fields depending on the another field value

validations

#problem: validate field2 and field3 depending on value of field1
validates :field1, presence: true

validates :field2, presence: true, :if => Proc.new {|o| o.field1 == "Yes" }
validates :field3, presence: true, :if => Proc.new {|p| p.field1 == "No" }