Rails 5 データベースに値が入らない

こちらを参考にしてやってみたのですが、データベースにうまく値を入れられないようです。

devise にusername カラムを追加し、usernameを登録できるようにする。
https://qiita.com/yasuno0327/items/ff17ddb6a4167fc6b471

何が原因でしょうか。

irb(main):001:0> User.columns.last
=> #<ActiveRecord::ConnectionAdapters::Column:0x0000000006948738 @name="username", @table_name="users", @sql_type_metadata=#<ActiveRecord::ConnectionAdapters::SqlTypeMetadata:0x0000000006948788 @sql_type="varchar", @type=:string, @limit=nil, @precision=nil, @scale=nil>, @null=true, @default=nil, @default_function=nil, @collation=nil, @comment=nil>

@type=:stringっていうのが少し気になりました。

ログ

Started POST "/users" for 127.0.0.1 at 2018-07-07 03:13:39 +0900
Processing by Devise::RegistrationsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"9ZNg9busSasOKl7x6G1KFCxhrz/NwEUmuiBVShh1l6MkcY3eWmBx/T1NiApXlDME8WMewuBtJJG6zb5u1zoeSA==", "user"=>{"username"=>"hoge ", "email"=>"yuis.twitter+hoge3@gmail.com", "password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]"}, "commit"=>"Sign up"}
   (0.0ms)  begin transaction
  ↳ C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/activerecord-5.2.0/lib/active_record/log_subscriber.rb:98
  User Exists (0.0ms)  SELECT  1 AS one FROM "users" WHERE "users"."email" = ? LIMIT ?  [["email", "yuis.twitter+hoge3@gmail.com"], ["LIMIT", 1]]
  ↳ C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/activerecord-5.2.0/lib/active_record/log_subscriber.rb:98
  User Create (2.0ms)  INSERT INTO "users" ("email", "encrypted_password", "confirmation_token", "confirmation_sent_at", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?, ?)  [["email", "yuis.twitter+hoge3@gmail.com"], ["encrypted_password", "$2a$11$Hx4uaEqj0fOBzFSb/WgYSudELxdFdt7ZH3wDJeb/7Wju/XSoqY.ae"], ["confirmation_token", "Mdp-gfoGksY9xEat9Rw5"], ["confirmation_sent_at", "2018-07-06 18:13:39.318612"], ["created_at", "2018-07-06 18:13:39.318612"], ["updated_at", "2018-07-06 18:13:39.318612"]]
  ↳ C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/activerecord-5.2.0/lib/active_record/log_subscriber.rb:98
   (62.8ms)  commit transaction
  ↳ C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/activerecord-5.2.0/lib/active_record/log_subscriber.rb:98
  Rendering devise/mailer/confirmation_instructions.html.erb
  Rendered devise/mailer/confirmation_instructions.html.erb (1.0ms)