use #blank? instead #nil?

app/models/commit.rb

@@ -194,7 +194,7 @@ class Commit
   def description
     return safe_message if full_title.length >= 100
-    if safe_message.nil?
+    if safe_message.blank?
       no_commit_message
     else
       safe_message.split("\n", 2)[1].try(:chomp)