up gitignore

.gitignore

@@ -1,4 +1,15 @@
 # Default ignored files
 /shelf/
 /.idea/workspace.xml
-*/target/
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+/simple/target/