add clone_all.sh

scripts/.gitignore

@@ -0,0 +1 @@
+student_solutions/

scripts/clone_all.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -xe
+
+groups=$(cargo run -- projects 20197)
+branch="2-performance"
+
+mkdir -p student_solutions
+cd student_solutions
+
+while read -ra arr; do
+  git clone --branch $branch "${arr[1]}"
+done <<<"$groups"