/pools: make autocomplete use index.

`name ilike ?` doesn't use the index. Use `lower(name) like ?` instead.

app/models/pool.rb

@@ -45,9 +45,9 @@ class Pool < ActiveRecord::Base
     end
 
     def name_matches(name)
-      name = name.tr(" ", "_")
+      name = normalize_name_for_search(name)
       name = "*#{name}*" unless name =~ /\*/
-      where("name ilike ? escape E'\\\\'", name.to_escaped_for_sql_like)
+      where("lower(name) like ? escape E'\\\\'", name.to_escaped_for_sql_like)
     end
 
     def search(params)
@@ -139,6 +139,10 @@ class Pool < ActiveRecord::Base
     name.gsub(/\s+/, "_")
   end
 
+  def self.normalize_name_for_search(name)
+    normalize_name(name).mb_chars.downcase
+  end
+
   def self.normalize_post_ids(post_ids, unique)
     hoge = post_ids.scan(/\d+/)
     if unique