added caravel as submodule

.gitmodules

diff --git a/.gitmodules b/.gitmodules
index e69de29..5bdfdae 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "caravel"]
+	path = caravel
+	url = https://github.com/efabless/caravel

caravel

diff --git a/caravel b/caravel
new file mode 160000
index 0000000..20308f5
--- /dev/null
+++ b/caravel
@@ -0,0 +1 @@
+Subproject commit 20308f5d46605cb0e0799a0f26142e729bbaaebe