add Cargo.lock to gitignore file by default

See the [official recommendation](http://doc.crates.io/guide.html#cargotoml-vs-cargolock)

> * If you're building a library, put Cargo.lock in your .gitignore.
> * If you're building an executable, check Cargo.lock into git.

diff --git a/Rust.gitignore b/Rust.gitignore
index 37727f91cbeed77698ea9cd0bcd5f074caf34739..94408df698076415531e72042a941afe7e6bf911 100644 (file)
--- a/Rust.gitignore
+++ b/Rust.gitignore
@@ -9,3 +9,4 @@
 
 # Generated by Cargo
 /target/
+Cargo.lock