public async Task <Organization> AddContactAsync(long organizationId, long contactId)
        {
            var entityExists = await _organizationContactRepository.CheckIfOrganizationContactExistsAsync(contactId, organizationId);

            if (entityExists)
            {
                throw new Exception("try to add a connection, while there is already one");
            }

            var organization = await GetByIdAsync(organizationId);

            var contact = await _contactRepository.GetByIdAsync(contactId);

            if (organization == null || contact == null)
            {
                throw new Exception("can not find entities with given ids");
            }

            var organizationContact = new OrganizationContact()
            {
                Organization = organization, Contact = contact
            };

            await _organizationContactRepository.CreateAsync(organizationContact);

            return(organization);
        }