gistfile1.rb

 # PATCH/PUT /users/:id.:format
  def update
    # authorize! :update, @user
    respond_to do |format|
      if @user.update(user_params)
        sign_in(@user == current_user ? @user : current_user, :bypass => true)
        format.html { redirect_to @user, notice: 'Your profile was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @user.errors, status: :unprocessable_entity }
      end
    end
  end