update README

README.md

@@ -14,18 +14,21 @@ The master branch is known to compile with:
 
 The recommended way to build the development is using OPAM. To avoid conflicts
 with existing packages, we recommend to create a new opam switch:
-
-`opam switch ra-gps --alias-of=4.02.3`
-
+```
+opam switch ra-gps --alias-of=4.02.3
+```
 It should work for any compiler version upwards of 4.01.0. After compiling
 OCaml, the new switch needs to be activated in your current shell. opam will
 print the necessary instructions.
 
-To find all the dependencies of ra-gps, opam needs to know about the Coq opam archive. This can be achieved by executing
-`opam repo add coq-released https://coq.inria.fr/opam/released`
+To find all the dependencies of ra-gps, opam needs to know about the Coq and Iris opam archives. This can be achieved by executing
+```
+opam repo add coq-released https://coq.inria.fr/opam/released
+opam repo add iris-dev https://gitlab.mpi-sws.org/FP/opam-dev.git
+```
 
-Now, go to [coq/ra](coq/ra) and execute `make build-dep` to install all
-dependencies of ra-gps. Finally, execute "make" to build the development.
+Now, execute `make build-dep` to install all
+dependencies of ra-gps. Finally, execute `make` to build the development.
 
 ## Structure