diff --git a/Project.toml b/Project.toml
index 79ae11b3..05c62269 100644
--- a/Project.toml
+++ b/Project.toml
@@ -26,6 +26,7 @@ Compat = "2.2, 3, 4"
 DataStructures = "0.17, 0.18"
 FiniteDiff = "2.8.1"
 ForwardDiff = "0.10"
+Graphs = "1"
 Requires = "0.5, 1.0"
 StaticArrays = "1"
 VertexSafeGraphs = "0.2"