FIX: Bot mentioned check should be case insensitive.

plugins/discourse-narrative-bot/spec/discourse_narrative_bot/track_selector_spec.rb

@@ -427,6 +427,16 @@ describe DiscourseNarrativeBot::TrackSelector do
           expect(new_post.raw).to eq(random_mention_reply)
         end
 
+        it "should be case insensitive towards discobot's username" do
+          discobot_user.update!(username: 'DisCoBot')
+
+          post.update!(raw: 'Show me what you can do @discobot')
+          described_class.new(:reply, user, post_id: post.id).select
+          new_post = Post.last
+          expect(new_post.raw).to eq(random_mention_reply)
+        end
+
+
         describe 'rate limiting random reply message in public topic' do
           let(:topic) { Fabricate(:topic) }
           let(:other_post) { Fabricate(:post, raw: '@discobot show me something', topic: topic) }