DB設計

usersテーブル

Column	Type	Options
name	string	null: false, unique: true
email	string	null: false, unique:true
password	string	null: false

Association

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

groups テーブル

Column	Type	Options
name	string	null: false, unique: true

Association

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

massages テーブル

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

Association

• belongs_to :group
• belongs_to :user

groups_users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