Added doc for boundary conditions
Solves the following issue(s):
This should be adapted in #250
Core changes:
None
Model-specific changes:
None
Documentation changes:
Filled the section "Userguide: Boundary conditions".
Solves the following issue(s):
This should be adapted in #250
Core changes:
None
Model-specific changes:
None
Documentation changes:
Filled the section "Userguide: Boundary conditions".