groups_usersテーブル

Column	Type	Options
user	references	null: false, foreign_key: true
group	references	null: false, foreign_key: true

Association

• belongs_to :group
• belongs_to :user

usersテーブル

Column	Type	Options
name	string	null: false, unique: true,index: true
mail	string	null: false, unique: true
pass	integer	null: false

Association

• has_many:groups, through: :groups_users
• has_many:messages
• has_many:groups_users

groupsテーブル

Column	Type	Options
name	string	null: false

Association

• has_many:users, through: :groups_users
• has_many:messages
• has_many:groups_users

messagesテーブル

Column	Type	Options
message	text
image	string
user	references	null: false, foreign_key: true
group	references	null: false, foreign_key: true

Association

• belongs_to :group
• belongs_to :user