userテーブル

Column	Type	Options
name	string	null: false
mail	string	null: false
password	string	null: false

Association

• has_many :groups, through: :members
• has_many :messages

groupテーブル

Column	Type	Options
group_name	string	null: false

Association

• has_many :users, through: :members
• has_many :messages

membersテーブル

Column	Type	Options
user_id	integer	null: false, foreign_key: true
group_id	integer	null: false, foreign_key: true

Association

• belongs_to :group
• belongs_to :user

messagesテーブル

Column	Type	Options
body	text	null: false
image	string	null: false
group_id	integer	null: false, foreign_key: true
user_id	integer	null: false, foreign_key: true

Association

• belongs_to :user
• belongs_to :group