Updated regressions log
+ BM25 tuned parameters for MS MARCO doc
+ Doc2query on MS MARCO passage
The following change log details commits to regression tests that alter effectiveness and the addition of new regression tests.
This documentation is useful for figuring why results may have changed over time.
+### June 20, 2019
+
++ commit [`86be3d2`](https://github.com/castorini/anserini/commit/86be3d21ea8bdf9309ca5f85362c2782c3898a19) (6/20/2019)
++ commit [`b656da3`](https://github.com/castorini/anserini/commit/b656da3ed0ec3fa385dfdb9df0d153cd9a78bd7d) (6/20/2019)
+
+Added new Doc2query regression `msmarco-passage-doc2query` to replicate [Nogueira et al. (arXiv 2019)](https://arxiv.org/abs/1904.08375) on the MS MARCO passage ranking task.
+Added tuned BM25 parameters to `msmarco-doc` regression.
+Associated documentation updated.
+
### June 12, 2019
+ commit [`75e36f9`](https://github.com/castorini/anserini/commit/75e36f97f7037d1ceb20fa9c91582eac5e974131) (6/9/2019)
