Adding git modules.
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..aea016c
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,32 @@
+[submodule "prjxray"]
+ path = prjxray
+ url = ../prjxray
+ branch = .
+[submodule "prjtrellis"]
+ path = prjtrellis
+ url = ../prjtrellis
+ branch = .
+[submodule "third_party/icestorm"]
+ path = third_party/icestorm
+ url = ../third_party/icestorm
+ branch = .
+[submodule "third_party/nextpnr"]
+ path = third_party/nextpnr
+ url = ../third_party/nextpnr
+ branch = .
+[submodule "third_party/Surelog"]
+ path = third_party/Surelog
+ url = ../third_party/Surelog
+ branch = .
+[submodule "third_party/verible"]
+ path = third_party/verible
+ url = ../third_party/verible
+ branch = .
+[submodule "third_party/vtr-verilog-to-routing"]
+ path = third_party/vtr-verilog-to-routing
+ url = ../third_party/vtr-verilog-to-routing
+ branch = .
+[submodule "third_party/yosys"]
+ path = third_party/yosys
+ url = ../third_party/yosys
+ branch = .
