add initial db_test: creating and deleting subscribers

Change-Id: I2a0d277f55162bf5ceb0fc7d50390f2994daed71
diff --git a/tests/db/db_test.ok b/tests/db/db_test.ok
new file mode 100644
index 0000000..26cefd1
--- /dev/null
+++ b/tests/db/db_test.ok
@@ -0,0 +1,2 @@
+db_test.c
+Done