An array of allergies (new model) associated to patients

[tangollama]

Track allergies on a patient, for the purposes of eventual features to trace drug interactions. Philosophically, we don't want HospitalRun handling the interaction service. Instead, we'd prefer to both trace the list of allergies as well as the list of allergic reactions/interactions from a separate, centralized service. However, to to any of that, we need the allergies identified and associated with patient.

[trevorbunch]

If you are using an external drug / allergy interaction service (e.g.
through a Vidal or Lexicomp) - you should plan to use a standard Allergy Dx
code system (e.g. ICD-10-CM).

[mnorbeck]

@tangollama agree that the allergies need to be directly associated with the patient. Say, as opposed to be down in a visit. Doctors want to be able to quickly see the known allergies, similar to diagnosis, directly from patient info.

[jkleinsc]

Closed by #679