/**
   * Find all groups with the count of their posts.
   *
   * @return List[GroupLink]
   */
  def findGroupLinks() = {
    DB withSession { implicit session =>
      val q = (for {
        groups <- slickGroups
        posts <- slickPosts if groups.id === posts.groupId
      } yield (groups.title, posts)).groupBy(_._1.title)

      q.map {
        case (groupTitle, groupPosts) => GroupLink(groupTitle, groupPosts.length)
      }.list
    }
  }

[error] /Users/arturgajewski/workspace/scala/cobase-pro/app/models/daos/GroupDAO.scala:41: type mismatch;
[error]  found   : scala.slick.lifted.Column[String]
[error]  required: String
[error]         case (groupTitle, groupPosts) => GroupLink(groupTitle, groupPosts.length)
[error]                                                    ^
[error] /Users/arturgajewski/workspace/scala/cobase-pro/app/models/daos/GroupDAO.scala:41: type mismatch;
[error]  found   : scala.slick.lifted.Column[Int]
[error]  required: Int
[error]         case (groupTitle, groupPosts) => GroupLink(groupTitle, groupPosts.length)
[error]                                                                           ^
[error] /Users/arturgajewski/workspace/scala/cobase-pro/app/models/services/GroupService.scala:23: type mismatch;
[error]  found   : List[Unit]
[error]  required: List[models.GroupLink]
[error]   def findGroupLinks(): List[GroupLink] = groupDAO.findGroupLinks()