#1189 - documentation for user subject type

public/documentation/sideBarDocumentation/SubjectType.md

@@ -16,4 +16,8 @@ Use the group type to define groups of a certain subject type. eg: A school migh
 
 A household is a special kind of group. Groups roles are predefined when you choose household type, but you can choose any of the existing Person as member subject.
 
+**User**
+
+A user subject type is a type that can be used to manage information about users of the system. Each user will have one subject created based on this subject type. This subject and any data collected against it will or encounters and enrolments are only for single user.
+
 [Learn more about Avni's domain model](https://avni.readme.io/docs/avnis-domain-model-of-field-based-work)