Use ILIKE in Project.search_by_title

Similar to the changes made to Project.search the method
Project.search_by_title now also uses Arel so it can automatically use
ILIKE/LIKE instead of the lower() function.

app/models/project.rb

@@ -298,7 +298,10 @@ class Project < ActiveRecord::Base
     end
 
     def search_by_title(query)
-      non_archived.where('LOWER(projects.name) LIKE :query', query: "%#{query.downcase}%")
+      pattern = "%#{query}%"
+      table   = Project.arel_table
+
+      non_archived.where(table[:name].matches(pattern))
     end
 
     def find_with_namespace(id)

spec/models/project_spec.rb

@@ -698,4 +698,20 @@ describe Project, models: true do
       project.expire_caches_before_rename('foo')
     end
   end
+
+  describe '.search_by_title' do
+    let(:project) { create(:project, name: 'kittens') }
+
+    it 'returns projects with a matching name' do
+      expect(described_class.search_by_title(project.name)).to eq([project])
+    end
+
+    it 'returns projects with a partially matching name' do
+      expect(described_class.search_by_title('kitten')).to eq([project])
+    end
+
+    it 'returns projects with a matching name regardless of the casing' do
+      expect(described_class.search_by_title('KITTENS')).to eq([project])
+    end
+  end
 end