A hardware development company wants to track their downtimes due to issues in their own network. Instead of using a program like Jira, they want to develop their own issue tracker.
Based upon the following screenshot you have to model an ER diagram:

Solution
Schema

The diagram can also be found online on dbdiagram.io.
Table user {
id integer [not null, unique]
firstname char(255) [not null]
lastname char(255) [not null]
}
Table category {
id integer [not null, unique]
name char(255) [not null, unique]
}
Table priority {
id integer [not null, unique]
name char(255) [not null, unique]
}
Table status {
id integer [not null, unique]
name char(255) [not null, unique]
}
Table issue {
id integer [not null, unique]
description text
occurred_at date [not null]
solution text
// `priority_id` and `status_id` are totally valid candidates for an enum type. In most cases you don't want to change the tuples for those tables
// e.g.
// enum priority { LOW, MEDIUM, HIGH }
priority_id integer [not null, ref: > priority.id]
// e.g.
// enum status { OPEN, IN_PROGRESS, CLOSED }
status_id integer [not null, ref: > status.id]
owner_id integer [not null, ref: > user.id]
category_id integer [not null, ref: > category.id]
// if we want to go with a `worklog` table, we can skip the `last edit` field:
// last_edited_at datetime [null]
}
Table worklog {
id integer [not null, unique]
description text [not null]
created_at datetime [not null]
issue_id integer [not null, ref: > issue.id]
}