[BE] ERD

issue 75

Table study {
  id Integer [primary key]
  name String
  study_type String
}

Table pomodoro {
  study_id Integer [primary key]
  total_cycle Integer
  time_per_cycle Integer
}

Table participant_code {
  id Integer [primary key]
  study_id Integer
  code String 
}

Table member {
  id Integer [primary key]
  nickname String 
}

Table member_progress {
  id Integer [primary key]
  study_id Integer
  member_id Integer 
  progress_type String 
  is_done boolean
} 

Table pomodoro_progress {
  member_progress_id Integer
  current_cycle Integer
  study_status String
}

Table member_record {
  id Integer [primary key]
  member_progress_id Integer
  record_type String
}

Table pomodoro_record {
  member_record_id Integer
  cycle Integer
  plan JSON
  retrospect JSON
  template_version String
}

Ref fk_study_to_participant_code: study.id - participant_code.study_id

Ref fk_pomodoro_to_study: pomodoro.study_id - study.id

Ref fk_member_progress_to_member: member_progress.member_id > member.id
Ref fk_member_progress_to_study: member_progress.study_id > study.id

Ref fk_pomodoro_progress_to_member_progress: pomodoro_progress.member_progress_id - member_progress.id

Ref fk_pomodoro_record_to_member_record: pomodoro_record.member_record_id - member_record.id 
Ref fk_member_record_to_member_progress: member_record.member_progress_id > member_progress.id