Update README.md

Author: seanbone

README.md

@@ -1,3 +1,11 @@
 # meteor_pbs18
 
-Meteorite crashing into the sea - Physically-Based Simulation HS18 project
+Meteorite crashing into the sea - Physically-Based Simulation HS18 project.
+
+Authors: Silvia Nauer, Mikael Stellio, Sean Bone.
+
+# Cloning with submodules
+This Git repository has a submodule for libigl. To clone it correctly use either of the following:
+
+    git clone --recurse-submodules [email protected]:bones/meteor_pbs18.git
+    git clone --recurse-submodules https://gitlab.ethz.ch/bones/meteor_pbs18.git