Update README.adoc

Co-authored-by: Koichi ITO <[email protected]>

Author: masato-bkn

README.adoc

@@ -1102,6 +1102,7 @@ User.where.not('status = ? AND plan = ?', 'active', 'basic')
 ----
 
 === Redundant `all` [[redundant-all]]
+
 Using `all` as a receiver for Active Record query methods is redundant. 
 The result won't change without `all`, so it can be removed.