Created a minimum running example.

core/simulation.jl

+### Persephone - a socio-economic-ecological model of European agricultural landscapes.
+###
+### This file includes the core functions for initialising and running simulations.
+###
+
+function initsim()
+    #TODO
+end
+
+function runsim()
+    #TODO
+end
+
+function simulate()
+    initsim()
+    runsim()
+    print("Simulation ran. Nothing happened.")
+    #TODO
+end

persephone.jl

+### Persephone - a socio-economic-ecological model of European agricultural landscapes.
+###
+### Daniel Vedder <daniel.vedder@idiv.de>
+### Lea Kolb <lea-deborah.kolb@idiv.de>
+### (c) 2022, licensed under the terms of the MIT license
+###
+### This file defines the module (= "library") for the Persephone model.
+### To run the model, either execute `run.jl` from the commandline,
+### or import the module using your own wrapper script or software.
+###
+
+module Persephone
+
+## define dependencies
+using
+    Agents,
+    ArgParse
+
+## define exported functions and variables
+export
+    simulate
+
+## include all module files
+include("core/input.jl")
+
+include("core/output.jl")
+
+include("crop/crops.jl")
+
+include("ecology/ecology.jl")
+
+include("farm/farm.jl")
+
+include("core/simulation.jl")
+
+end

run.jl

+#!/usr/bin/env julia
+# A very thin wrapper to start a Persephone simulation.
+# (This is not included in persephone.jl in order to enable the latter to
+# be used as a library, without automatically launching a simulation.)
+
+include("persephone.jl")
+using .Persephone
+
+simulate()