fixed schema creation

include/matador/orm/schema.hpp

@@ -3,6 +3,8 @@
 
 #include "matador/object/repository.hpp"
 
+#include "matador/sql/query_context.hpp"
+
 namespace matador::sql {
 class connection_pool;
 }
@@ -49,6 +51,10 @@ public:
   [[nodiscard]] utils::result<std::vector<object::attribute>, utils::error> describe_table(const std::string &table_name) const;
   [[nodiscard]] utils::result<bool, utils::error> table_exists(const std::string &table_name) const;
 
+private:
+   sql::query_context build_add_constraint_context( const object::repository_node& node, const class object::constraint& cons ) const;
+   sql::query_context build_drop_constraint_context( const object::repository_node& node, const class object::constraint& cons ) const;
+
 private:
   object::repository repo_;
   sql::connection_pool &pool_;