DB設計

users_table

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

###Asociation

• has_many :messages
• has_many :groups, through: :group_users
• has_many :group_users

##groups_table

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

###Asociation

• has_many :users,through: :group_users
• has_many :group_users
• has_many :messages

##group_user_table

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

###Asociation

• belongs_to :user
• belongs_to :group

##messages_table

Column	Type	Options
body	text
image	string
user_id	reference	null:false,foreign_key:true
groups_id	reference	null:false,foreign_key:true

###Asociation

• belongs_to :user
• belongs_to :group