solution_controller.rb

class SolutionsController < AuthenticatedController

  before_filter :require_admin, only: :index

  def index
    @solutions = Solution.scoped
  end

  def create
    solution = Solution.new(params[:solution])
    solution.user = current_user
    solution.save!

    flash[:notice] = "Good job with this task!"
    redirect_to dashboard_path
  end

  def edit
    @solution = Solution.find(params[:id])
    @task = @solution.task
  end

  def update
    @solution = Solution.find(params[:id])
    @task = @solution.task

    if @solution.update_attributes(params[:solution])
      redirect_to dashboard_path, notice: "Solution was updated."
    else
      render :edit
    end
  end

  def destroy
    Solution.find(params[:id]).destroy
    redirect_to dashboard_path, notice: "Solution was removed"
  end

end

task.rb

class Task < ActiveRecord::Base
  attr_accessible :title, :description, :tag_ids

  validates_presence_of :title, :description

  has_many :solutions, dependent: :destroy
  has_many :users, through: :solutions

  has_many :taggings
  has_many :tags, through: :taggings

  belongs_to :next_step, class_name: "Task"
  has_one :previous_step, class_name: "Task", foreign_key: "next_step_id"

  # nasledujici dve metody se pouzivaji pouze pro zjisteni, zda u instance ukolu na kteoru je metoda solved_by volana
  # ma uzivatel splnene solution - jinymi slovy, jestli ukol uz vyresil.
  def solution_for(user)
    solutions.where(user_id: user.id).first
  end

  def solved_by?(user)
    !!solution_for(user)
  end

  # vraci pouze mozne ukoly pro uzivatele (ne ty, ktere jiz ma vyresene)
  # nebo ty u kterych jeste nema vyreseny predchazejici krok - task.previous_step
  def self.available_for(user)
    Task.all.reject do |task|
      task.solved_by?(user) || (task.previous_step && !task.previous_step.solved_by?(user))
    end
  end

end

utilities.js

window.util = {

  // Function which return number of words.
  // I need to give it text where I need to know number of words in it.
  countWords: function(text) {
    var words = text.split(" ");
    var count;

    if (words[words.length - 1] === "") {
      count = words.length - 1;
    } else {
      count = words.length;
    }

    return count;
  },

  // Function which returns number of stars according to number of words
  // I need to give it number of words.
  starCount: function(count) {
    if (count > 10 && count < 70) {
      return 1;
    } else if (count >= 70 && count < 200) {
      return 2;
    } else if (count >= 200) {
      return 3;
    } else {
      return 0;
    }
  }
};