This postfunction allows to set assignee from some project role. It may be:
role member with minimum amount of issues in current project;
role member with minimum remaining estimates in current project;
role member who was the last assignee of this issue;
default role member. Set user property to the user, who should be the default role member.
The name of the property is a role name. The value of the property is a code of the project, where the user should be a default role member. For example: Property name = Developer and Property value = Dev