programs/lfx: add our 2025 project idea

Add our project idea.

Signed-off-by: Giedrius Statkevičius <[email protected]>

programs/lfx-mentorship/2025/01-Mar-May/project_ideas.md

@@ -208,3 +208,20 @@ In this project you will, together with your mentor and the TUF community, ident
   - TBD
 - Upstream Issue (URL): TBD, https://github.com/theupdateframework/tuf-on-ci/issues/39 (initial ideas)
 
+### Thanos
+
+#### Add support for new PromQL aggregations
+
+[Thanos](https://thanos.io) has its own PromQL ([Prometheus](https://prometheus.io) querying language) engine. The original PromQL engine recently added support for new aggregations. We are missing support for them in the [Thanos PromQL engine](https://github.com/thanos-io/promql-engine).
+
+In this project you will implement support for `limitk` and `limit_ratio`. See [issue](https://github.com/thanos-io/promql-engine/issues/515). This will unblock users who need this functionality.
+
+The project is interesting because you will learn how query engines are implemented, about distributed query execution.
+
+- Expected Outcome: `limitk`, `limit_ratio` are supported in the Thanos PromQL engine (local & distributed modes), tests are written for them
+- Recommended Skills: Go programming language experience
+- Mentor(s): #
+  - Giedrius Statkevičius (@GiedriusS, [email protected])
+  - Saswata Mukherjee (@saswatamcode, [email protected])
+- Upstream Issue (URL): https://github.com/thanos-io/promql-engine/issues/515
+