Add logger

.rustfmt.toml

@@ -0,0 +1,15 @@
+# See full list at:
+# https://github.com/rust-lang-nursery/rustfmt/blob/master/Configurations.md
+
+max_width = 80
+format_strings = true
+normalize_comments = true
+wrap_comments = true
+
+reorder_impl_items = true
+use_try_shorthand = true
+
+error_on_line_overflow = true
+error_on_unformatted = true
+
+unstable_features = true