Add bors integration
diff --git a/.travis.yml b/.travis.yml
index 55492aa..69d3a37 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,10 @@
+branches:
+  only:
+    # This is where pull requests from "bors r+" are built.
+    - staging
+    # This is where pull requests from "bors try" are built.
+    - trying
+
 language: rust
 rust:
   - nightly-2019-11-06