added basic unit test

test/test_config.cc

@@ -0,0 +1,13 @@
+#include <gtest/gtest.h>
+#include <libconfig.h>
+
+TEST(config, is_loadable)
+{
+    config_t config;
+    config_init(&config);
+
+    int result = config_read_file(&config, "webfused.conf");
+    ASSERT_EQ(CONFIG_TRUE, result);
+
+    config_destroy(&config);
+}