Limit size to 20 char for the custom tab title

app/models/custom_tab.rb

@@ -3,5 +3,5 @@
 class CustomTab < ApplicationRecord
   belongs_to :enterprise, optional: false
 
-  validates :title, presence: true
+  validates :title, presence: true, length: { maximum: 20 }
 end

spec/models/custom_tab_spec.rb

@@ -9,5 +9,7 @@ describe CustomTab do
 
   describe 'validations' do
     it { is_expected.to validate_presence_of(:title) }
+
+    it { is_expected.to validate_length_of(:title).is_at_most(20) }
   end
 end

spec/system/admin/enterprises_spec.rb

@@ -753,6 +753,15 @@ describe '
               expect(page).to have_content("Custom tab title can't be blank")
               expect(distributor1.reload.custom_tab).to be_nil
             end
+
+            it "can't save custom tab fields if title is too long" do
+              fill_in "enterprise_custom_tab_attributes_title", with: "a" * 21
+              fill_in_trix_editor "custom_tab_content", with: "Custom tab content"
+              click_button 'Update'
+              expect(page).
+                to have_content("Custom tab title is too long (maximum is 20 characters)")
+              expect(distributor1.reload.custom_tab).to be_nil
+            end
           end
 
           context "when custom tab is already created" do