App crash if exception or promise is rejected

[medamineziraoui]

Currently the hole app crash if an exception or promise is rejected, we need to prevent that and make sure that a failure in the execution won't cause the application to crash

[medamineziraoui]

• Check if we can prevent that from happening in the express part, until this moment I didn't find evidence that this is possible, we need to always provide next() and handle correctly
• Add a system at node level to handle crashes.
• Add system to shutdown instance gracefully
• Add system to add workers, this will allow us to add more instances and restart them if they fail. use previous version of throng lib

[medamineziraoui]

• Add PM2 to current project