Add new nutils solver to README list

perpendicular-flap/README.md

@@ -37,6 +37,8 @@ Solid participant:
 
 * DUNE. For more information, have a look at the [experimental DUNE adapter](https://github.com/precice/dune-adapter) and send us your feedback.
 
+* Nutils. The structural model is currently limited to linear elasticity. For more information, have a look at the [Nutils adapter documentation](https://www.precice.org/adapter-nutils.html). This Nutils solver requires at least Nutils v8.0.
+
 * OpenFOAM (solidDisplacementFoam). For more information, have a look at the [OpenFOAM plateHole tutorial](https://www.openfoam.com/documentation/tutorial-guide/5-stress-analysis/5.1-stress-analysis-of-a-plate-with-a-hole). The solidDisplacementFoam solver only supports linear geometry. For general solid mechanics procedures in OpenFOAM, see solids4foam.
 
 * solids4foam. Like for CalculuX, the geometrically linear solver is used by default. For more information, see the [solids4foam documentation](https://bitbucket.org/philip_cardiff/solids4foam-release/src/master/documentation/overview.md) This case currently (November 2022) only works with the `nextRelease` branch of solids4foam, which is only compatible with up to OpenFOAM v2012 and OpenFOAM 9 (as well as foam-extend, with which the OpenFOAM-preCICE adapter is not compatible), as well as the OpenFOAM-preCICE adapter v1.2.0 or later. Note that, since both solids4foam and preCICE rely on Eigen, and due to some [solids4foam-preCICE compatibility issue](https://github.com/precice/openfoam-adapter/issues/238), you need to build preCICE and solids4foam with the same Eigen version.