Add vector answer boxcar

[francis]

Now that we have VectorSearch, we can use that output get have an LLM figure out the desired answer.

[francis]

@jaigouk - one issue - if you do not force rebuild the search index, it does not work on followup calls. There must be something wrong with the save or reload functions.

[jaigouk]

I will try to simulate the situation within spec/boxcars/vector_search_spec.rb and try to add a new context

      context 'multiple calls' do
        it 'returns results with the same instace' do
          # first call
          first_result = vector_search.call(
            query: query,
            count: 1
          )

          # second call
          second_query = 'What is the first step to do when there is a harassment?'
          second_result = vector_search.call(
            query: second_query,
            count: 1
          )

          require 'debug'; debugger
        end
      end
    end

update: I checked the result and I think there is a bug. I will create a fix PR for hnswlib search. I will start working into this https://github.com/jaigouk/boxcars/pull/2 and open a PR in this repo when it is ready.