add handy script to find gc_roots

scripts/find_store_path_gc_roots.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env sh
+
+function find_store_path_gc_roots {
+    store_path="$(realpath $1)"
+    while IFS=' ' read -r gcroot derivation; do
+        if [[ ! $gcroot =~ ^/proc ]]; then
+            if nix-store -qR "$derivation" 2>/dev/null | grep -q "$store_path"; then
+				echo $gcroot
+            fi
+        fi
+    done < <(nix-store --gc --print-roots | awk '{print $1, $3}')
+}
+
+
+find_store_path_gc_roots "$@"