en:
  grape:
    errors:
      format: ! '%{attribute} %{message}'
      messages:
        coerce: 'is invalid'
        presence: 'is missing'
        regexp: 'is invalid'
        values: 'does not have a valid value'
        missing_vendor_option:
          problem: 'missing :vendor option.'
          summary: 'when version using header, you must specify :vendor option. '
          resolution: "eg: version 'v1', :using => :header, :vendor => 'twitter'"
        missing_mime_type:
          problem: 'missing mime type for %{new_format}'
          resolution:
            "you can choose exist mime type from Grape::ContentTypes::CONTENT_TYPES
            or add your own with content_type :%{new_format}, 'application/%{new_format}'
            "
        invalid_with_option_for_represent:
          problem: 'You must specify an entity class in the :with option.'
          resolution: 'eg: represent User, :with => Entity::User'
        missing_option: 'You must specify :%{option} options.'
        invalid_formatter: 'cannot convert %{klass} to %{to_format}'
        invalid_versioner_option:
          problem: 'Unknown :using for versioner: %{strategy}'
          resolution: 'available strategy for :using is :path, :header, :param'
        unknown_validator: 'unknown validator: %{validator_type}'
        unknown_options: 'unknown options: %{options}'
        incompatible_option_values: '%{option1}: %{value1} is incompatible with %{option2}: %{value2}'

en:
  grape:
    errors:
      format: ! '%{attribute} %{message}'
      messages:
        coerce: 'is invalid'
        presence: 'is missing'
        regexp: 'is invalid'
        values: 'does not have a valid value'
        missing_vendor_option:
          problem: 'missing :vendor option.'
          summary: 'when version using header, you must specify :vendor option. '
          resolution: "eg: version 'v1', :using => :header, :vendor => 'twitter'"
        missing_mime_type:
          problem: 'missing mime type for %{new_format}'
          resolution:
            "you can choose existing mime type from Grape::ContentTypes::CONTENT_TYPES
            or add your own with content_type :%{new_format}, 'application/%{new_format}'
            "
        invalid_with_option_for_represent:
          problem: 'You must specify an entity class in the :with option.'
          resolution: 'eg: represent User, :with => Entity::User'
        missing_option: 'You must specify :%{option} options.'
        invalid_formatter: 'cannot convert %{klass} to %{to_format}'
        invalid_versioner_option:
          problem: 'Unknown :using for versioner: %{strategy}'
          resolution: 'available strategy for :using is :path, :header, :param'
        unknown_validator: 'unknown validator: %{validator_type}'
        unknown_options: 'unknown options: %{options}'
        incompatible_option_values: '%{option1}: %{value1} is incompatible with %{option2}: %{value2}'

Fix EN on missing_mime_type resolution message
Fix EN on missing_mime_type resolution message

Instead of "you can choose exist", the correct is "you can choose existing".