Overwrite Label#to_s to ease debugging

Since a label is considered "unique" based on its name, overwriting `to_s` makes sense to aid debugging.

app/models/label.rb

@@ -72,6 +72,10 @@ def to_h
     }.compact
   end
 
+  def to_s
+    name
+  end
+
   def self.ransackable_attributes(_auth_object = nil)
     %w[name]
   end

spec/models/label_spec.rb

@@ -6,4 +6,13 @@
   describe 'validations' do
     it { is_expected.to validate_presence_of(:name) }
   end
+
+  describe '#to_s' do
+    let(:label_name) { 'Test Label' }
+    let(:label) { described_class.new(name: label_name) }
+
+    it 'returns the label name' do
+      expect(label.to_s).to eq label_name
+    end
+  end
 end