Be able to create chat room

```
$ rails g model ChatRoom name:string chat:json
$ bundle exec rake db:migrate
$ rails g controller chat_rooms index new room
$ vim app/controllers/chat_rooms_controller.rb
$ vim app/views/chat_rooms/_form.html.haml
$ vim app/views/chat_rooms/index.html.haml
$ vim app/views/chat_rooms/new.html.haml
$ vim app/views/chat_rooms/room.html.haml
$ vim config/routes.rb
```
Ignore *.swp, .secret, *~, *.env, .DS_Store

```
$ vim .gitignore
```
Be able to view chat room list

```
$ vim app/views/chat_rooms/index.html.haml
```
Be able to delete chat room

```
$ vim app/views/chat_rooms/index.html.haml
$ vim config/routes.rb
```
Be able to clear chat history

```
$ vim app/controllers/chat_rooms_controller.rb
$ vim app/models/chat_room.rb
$ vim app/views/chat_rooms/room.html.haml
```
Be able to chat on multi room

```
$ vim app/controllers/chat_rooms_controller.rb
$ vim app/models/chat_room.rb
$ vim app/views/chat_rooms/room.html.haml
$ vim config/routes.rb
```
Be able to chat's content is not leaked to other chat room

```
$ vim app/controllers/chat_rooms_controller.rb
$ vim app/views/chat_rooms/room.html.haml
```
Delete initial message by initialized chat
Fix bug:To leak contents from other chat that is visited once

```
$ vim app/controllers/chat_rooms_controller.rb
$ vim app/views/chat_rooms/room.html.haml
```
Move error page when exeption error series

```
$ vim app/controllers/application_controller.rb
$ vim config/routes.rb
$ vim public/404.html
```
Create custom error page, 404, 500

```
$ mkdir app/views/errors/
$ vim app/controllers/application_controller.rb
$ vim app/views/errors/error_404.html.haml
$ vim app/views/errors/error_500.html.haml
```
Change root page chat_room#index

```
$ vim config/routes.rb
```