Added comments to the autotesting script

scripts/autotest.sh

@@ -1,5 +1,15 @@
 #!/bin/bash
 
+# Usage:
+# cd astaroth
+# source ./sourceme.sh
+# autotest.sh
+#
+# If you need slurm or to pass something before ./ac_run, set the variable
+# SRUN_COMMAND before calling this script.
+#
+# F.ex. on Taito SRUN_COMMAND="srun --gres=gpu:k80:4 --mem=24000 -t 00:14:59 -p gputest --cpus-per-task 1 -n 1"
+
 results=()
 
 # Parameters