Add distance threshold optimizer classes (#292)

- add base, router, and cache threshold optimizer
- uses ranx to support eval metrics
- class is designed to receive a optimizer class in the case where
someone wants to supply their own without us having to make a release to
support something custom

Author: rbs333

.github/workflows/test.yml

@@ -105,7 +105,11 @@ jobs:
           AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
         run: |
           docker run -d --name redis -p 6379:6379 redis/redis-stack-server:latest
-          make test-notebooks 
+          if [[ "${{ matrix.python-version }}" > "3.9" ]]; then
+            make test-notebooks
+          else
+            poetry run test-notebooks --ignore ./docs/user_guide/09_threshold_optimization.ipynb
+          fi
 
   docs:
     runs-on: ubuntu-latest

README.md

@@ -222,6 +222,11 @@ embeddings = co.embed_many(
 ### Rerankers
 [Integrate with popular reranking providers](https://docs.redisvl.com/en/stable/user_guide/06_rerankers.html) to improve the relevancy of the initial search results from Redis
 
+### Threshold Optimization
+[Optimize distance thresholds for cache and router](https://docs.redisvl.com/en/stable/user_guide/09_threshold_optimization.html) with the utility `ThresholdOptimizer` classes.
+
+**Note:** only available for `python > 3.9`.
+
 
 
 ## 💫 Extensions