diff --git a/README.md b/README.md
index 8d37e7ba0..9278f0831 100644
--- a/README.md
+++ b/README.md
@@ -140,3 +140,5 @@ Indeed, you may suspect that.
 ## Why "Narwhals"?
 
 Because they are so awesome.
+
+Thanks to [Olha Urdeichuk](https://www.fiverr.com/olhaurdeichuk) for the illustration!
diff --git a/requirements-dev.txt b/requirements-dev.txt
new file mode 100644
index 000000000..dcc57d5f6
--- /dev/null
+++ b/requirements-dev.txt
@@ -0,0 +1,7 @@
+covdefaults
+pandas
+polars
+pre-commit
+pyarrow
+pytest
+pytest-cov