better.rb

Project = Struct.new(:title, :url)

def all(dir)
  Dir.chdir(dir) do
    Dir.glob('*').select { |d| File.directory?(d) }.map { |d|
      Project.new(d, "/project/#{d}")
    }
  end
end

all(project_dir).each do |project|
  puts "#{project.title} #{project.url}"
end

wrong.rb

def title
  self
end
def url
  "/project/#{self}"
end

def all
  Dir.chdir(Project_dir) do
    Dir.glob('*').select { |f| File.directory? f }
  end
end
 
all.each do |project|
  puts "#{project.title} #{project.url}"
end