Created get endpoint for ModuleResultsController. Invalid ModuleResult handling pending.
Finished get endpoint for ModuleResultsController.

Signed-off-by: Renan Fichberg
module_results_controller_spec syntax fixed and whitespaces removed
Removed unnecessary let! and using rails_helper
ModuleResultsController#get unit test, for when the id doesn't exists, fixed to raise the exception
Implemented metric_result endpoint for ModuleResultsController

Signed-off-by: Alessandro Palmeira <alessandro.palmeira@gmail.com>
Implemented children endpoint for ModuleResultsController

Signed-off-by: Renan Fichberg <rfichberg@gmail.com>