Chore/create skills rake task

# This pull request involves

* Rake task to populate skills
* Filters to skills accourding if the member is developer, designer or administrative
* Specs and testing
instead of using the global @user object, pass it as a parameter and do not create a new one inside of it, just return the value

```` ruby
def get_skills user
  case user.department
  when 'Development'
    Skill.development
  end
end
````

Also why are you using .first, all[1] and last ? Create a correct scope to get the skills per department