Add summer.sh

diff --git a/summer.sh b/summer.sh
new file mode 100755 (executable)
index 0000000..657e8bf
--- /dev/null
+++ b/summer.sh
@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+python -c "import sys; print(sum(float(l) for l in sys.stdin))"