Reorganizing tutorials

Author: ArnoStrouwen

docs/pages.jl

@@ -1,18 +1,19 @@
 pages = [
     "Home" => "index.md",
     "tutorials/ode_modeling.md",
-    "Tutorials" => Any["tutorials/acausal_components.md",
-        "tutorials/nonlinear.md",
-        "tutorials/initialization.md",
+    "Tutorials" => Any[
+        "Modeling Systems" => Any["tutorials/nonlinear.md",
         "tutorials/optimization.md",
-        "tutorials/modelingtoolkitize.md",
-        "tutorials/programmatically_generating.md",
         "tutorials/stochastic_diffeq.md",
         "tutorials/discrete_system.md",
-        "tutorials/parameter_identifiability.md",
-        "tutorials/bifurcation_diagram_computation.md",
-        "tutorials/SampledData.md",
-        "tutorials/domain_connections.md"],
+        "tutorials/programmatically_generating.md",
+        "tutorials/initialization.md",
+        "tutorials/modelingtoolkitize.md"]],
+    "Acausal Modeling" => Any["tutorials/acausal_components.md",
+        "tutorials/domain_connections.md",
+        "tutorials/SampledData.md"],
+    "Applications" => Any["tutorials/parameter_identifiability.md",
+        "tutorials/bifurcation_diagram_computation.md"],
     "Examples" => Any[
         "Basic Examples" => Any["examples/higher_order.md",
             "examples/spring_mass.md",