fixed PostgreSQL tests

test/backends/SessionFixture.cpp

@@ -1,15 +1,18 @@
 #include "SessionFixture.hpp"
 
+#include "connection.hpp"
+
 #include "catch2/catch_test_macros.hpp"
 
 namespace matador::test {
 
 SessionFixture::SessionFixture()
 : pool(connection::dns, 4)
-, ses({bus, pool}) {}
+, ses({bus, pool}, schema) {}
 
 SessionFixture::~SessionFixture() {
-  const auto result = ses.drop_schema();
+  const auto conn = pool.acquire();
+  const auto result = schema.drop(*conn);
   REQUIRE(result.is_ok());
 }