Added readme file

Author: NicolasSR

rom_application/RomManager_cantilever_NN_residual/readme.txt

@@ -0,0 +1,9 @@
+To run this code it is essential that you compile this particular branch of KratosMultiphysics:
+https://github.com/KratosMultiphysics/Kratos/tree/RomApp_RomManager_ResidualTrainingStructural
+
+It is also essential that you modify the scripts/standard_configure.sh file for Kratos' compilation by addig the next lines:
+add_app ${KRATOS_APP_DIR}/StructuralMechanicsApplication
+add_app ${KRATOS_APP_DIR}/ConstitutiveLawsApplication
+add_app ${KRATOS_APP_DIR}/RomApplication
+
+This will compile the needed applications from Kratos