add: database transactions

tests/run_tests.sh

@@ -8,7 +8,7 @@ alias valgrind_emgauwa="valgrind $2 --log-file=$working_dir/valgrind.log"
 
 
 rm -rf $working_bak
-mv $working_dir $working_bak
+[ -d $working_dir ] && mv $working_dir $working_bak
 
 mkdir -p $working_dir
 cd $working_dir
@@ -53,7 +53,7 @@ core_id=$!
 
 
 # wait for start
-sleep 3;
+sleep 5;
 curl -s -o /dev/null --retry 5 --retry-all-errors --retry-connrefused http://localhost:5000/api/v1/tags