diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index d79a1bf..aa03b8c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -33,7 +33,8 @@ make build && \
 	--verbose \
 	--bin-name srv \
 	--build-path ./testdata/server \
-	--build-args="-ldflags=\"-X 'main.Version=v1.0.0'\""
+	--build-args="-ldflags=\"-X 'main.Version=v1.0.0'\"" \
+	--extensions "go,txt"
 ```
 
 ### Running lint
diff --git a/testdata/server/data.txt b/testdata/server/data.txt
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/testdata/server/data.txt
@@ -0,0 +1 @@
+test