remove validation and add specs

spec/models/task_request_spec.rb

@@ -13,8 +13,4 @@ RSpec.describe TaskRequest, type: :model do
     subject { described_class }
     it { is_expected.to respond_to(:order_by_recent) }
   end
-
-  describe "#validations" do
-    it { should validate_numericality_of(:time_allowed).only_integer.is_greater_than_or_equal_to(2) }
-  end
 end