Replace where...first with find_by

  after_destroy do

    self.parent.update_comments_counter

    participation = author.participations.where(target_id: post.id).first

    participation = author.participations.find_by(target_id: post.id)

    participation.unparticipate! if participation.present?

  end

  end

  def set_read(user)

    if visibility = self.conversation_visibilities.where(:person_id => user.person.id).first

    visibility = conversation_visibilities.find_by(person_id: user.person.id)

    return unless visibility

    visibility.unread = 0

    visibility.save

  end

  end

  def participant_handles

    participants.map(&:diaspora_handle).join(";")

  def last_author

    return unless @last_author.present? || messages.size > 0

    @last_author_id ||= messages.pluck(:author_id).last

    @last_author ||= Person.includes(:profile).where(id: @last_author_id).first

    @last_author ||= Person.includes(:profile).find_by(id: @last_author_id)

  end

  def ordered_participants

  after_destroy do

    self.parent.update_likes_counter

    participation = author.participations.where(target_id: target.id).first

    participation = author.participations.find_by(target_id: target.id)

    participation.unparticipate! if participation.present?

  end

  end

  def increase_unread(user)

    if vis = ConversationVisibility.where(:conversation_id => self.conversation_id, :person_id => user.person.id).first

    vis = ConversationVisibility.find_by(conversation_id: conversation_id, person_id: user.person.id)

    return unless vis

    vis.unread += 1

    vis.save

  end

  end

  def message

    @message ||= Diaspora::MessageRenderer.new text

  def self.find_from_guid_or_username(params)

    p = if params[:id].present?

          Person.where(:guid => params[:id]).first

          Person.find_by(guid: params[:id])

        elsif params[:username].present? && u = User.find_by_username(params[:username])

          u.person

        else