```ruby
# frozen_string_literal: true

require "use_case/relationship/create"
require "use_case/relationship/destroy"
require "errors"

class Ajax::RelationshipController < AjaxController
  before_action :authenticate_user!

  def create
    params.require :target_user

    UseCase::Relationship::Create.call(
      current_user: current_user.screen_name,
      target_user: params[:target_user],
      type: params[:type]
    )
    @response[:success] = true
    @response[:message] = t(".success")
  rescue Errors::Base => e
    @response[:message] = t(e.locale_tag)
  ensure
    return_response
  end

  def destroy
    UseCase::Relationship::Destroy.call(
      current_user: current_user.screen_name,
      target_user: params[:target_user],
      type: params[:type]
    )
    @response[:success] = true
    @response[:message] = t(".success")
  rescue Errors::Base => e
    @response[:message] = t(e.locale_tag)
  ensure
    return_response
  end
end
```

Use full translation key for messages
user
```ruby
# frozen_string_literal: true

require "use_case/relationship/create"
require "use_case/relationship/destroy"
require "errors"

class Ajax::RelationshipController < AjaxController
  before_action :authenticate_user!

  def create
    params.require :target_user

    UseCase::Relationship::Create.call(
      current_user: current_user.screen_name,
      target_user: params[:target_user],
      type: params[:type]
    )
    @response[:success] = true
    @response[:message] = t('messages.friend.create.success')
  rescue Errors::Base => e
    @response[:message] = t(e.locale_tag)
  ensure
    return_response
  end

  def destroy
    UseCase::Relationship::Destroy.call(
      current_user: current_user.screen_name,
      target_user: params[:target_user],
      type: params[:type]
    )
    @response[:success] = true
    @response[:message] = t('messages.friend.create.success')
  rescue Errors::Base => e
    @response[:message] = t(e.locale_tag)
  ensure
    return_response
  end
end
```
assistant