include haystack in integration readme

Author: lucifertrj

integrations/README.md

@@ -5,4 +5,5 @@ Examples for adding Opik to a specific framework or library. Each folder covers
 | Integration | Description |
 |---|---|
 | [google_adk/](./google_adk/) | Google ADK — Trace an Agentic RAG router with Opik |
+| [haystack/](./haystack/) | Haystack — Trace a multi-agent web-search pipeline with Opik |
 | [otel/](./otel/) | OpenTelemetry — send OTel spans to Opik via OTLP |

integrations/haystack/README.md

@@ -0,0 +1,7 @@
+# Haystack + Opik
+
+Examples for tracing [Haystack](https://haystack.deepset.ai/) pipelines and Agents with Opik.
+
+| Example | Description |
+|---|---|
+| [multi_agent_web_search](./multi_agent_web_search/) | Trace a coordinator -> scout multi-agent web-search chain with Opik and Haystack pipeline |