diff --git a/.travis.yml b/.travis.yml
index 015b0b2..df783a2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -52,6 +52,7 @@ matrix:
         # Check rustfmt
         - name: "rustfmt check"
           rust: stable
+          env: RUSTUP_TOOLCHAIN="stable"
           install: rustup component add rustfmt
           script: cargo fmt -- --check
 
diff --git a/rust-toolchain b/rust-toolchain
new file mode 100644
index 0000000..9bea09d
--- /dev/null
+++ b/rust-toolchain
@@ -0,0 +1 @@
+nightly-2019-09-09