Under the title, we display a progress bar representing the validation rate of the skill.

A user progresses in a given skill (the validation rate increases) either by solving tasks associated with this skill directly, or by progressing on sub-skills of this skill.

Skills: content tab

• description
• prerequisites
• sub-skills
• parent skills

Skills have prerequisites: skills that should be mastered first, before attempting to learn this skill.

Skills also have sub-skills: finer-grained skills that compose their parent skills.

The same skill can be a prerequisite for several other skills, and can be a sub-skill of several skills.

[TODO: show skills for which the skill is a prerequisite?]