2つのテーブルを追加しました(#9)

[KAZYPinkSaurus]

9 で議論した通りの構成です｡

english-class-notify-db=# \d
                 List of relations
 Schema |          Name          |   Type   | Owner 
--------+------------------------+----------+-------
 public | submit_messages        | table    | root
 public | submit_messages_id_seq | sequence | root
 public | teacher_schedules      | table    | root
 public | teachers               | table    | root
(4 rows)

english-class-notify-db=# \d teachers
                     Table "public.teachers"
 Column  |         Type          | Collation | Nullable | Default 
---------+-----------------------+-----------+----------+---------
 id      | character varying(6)  |           | not null | 
 name    | character varying(30) |           | not null | 
 country | character varying(40) |           | not null | 
Indexes:
    "teachers_pkey" PRIMARY KEY, btree (id)

english-class-notify-db=# \d teacher_schedules
                        Table "public.teacher_schedules"
     Column      |            Type             | Collation | Nullable | Default 
-----------------+-----------------------------+-----------+----------+---------
 teacher_id      | character varying(6)        |           | not null | 
 slot_datetime   | timestamp without time zone |           | not null | 
 opened_datetime | timestamp without time zone |           | not null | 
Indexes:
    "teacher_schedules_pkey" PRIMARY KEY, btree (teacher_id, slot_datetime)

[solWat]

要件は満たしてると思うので、細かいとこ気にするよりも、マージして先に進めます。