Use guard clause instead of if-else statement

app/models/project_services/hipchat_service.rb

@@ -128,7 +128,8 @@ class HipchatService < Service
   end
 
   def markdown(text, options = {})
-    if text
+    return "" unless text
+
     context = {
       project: project,
       pipeline: :email
@@ -140,10 +141,8 @@ class HipchatService < Service
 
     html = Banzai.render(text, context)
     html = Banzai.post_process(html, context)
+
     sanitize html, attributes: %w(href title alt)
-    else
-      ""
-    end
   end
 
   def create_issue_message(data)