Fix suggested #49

[vrkansagara]

      if (isset($data['user_id'])) {
        $data = $this->mapField('user_id', 'id', $data);
      }

LmcUser/src/Mapper/UserHydrator.php

Line 64 in 341a0bd

$data = $this->mapField('user_id', 'id', $data);

#49

[visto9259]

As a I mentioned in the code review, the change should be made in the mapField() function as this is where the warning is raised.
And making the change in the mapField() function will cover all cases where a fromKey is not found in the array.