Add a changelog.

CHANGELOG.md

@@ -0,0 +1,44 @@
+# 1.0.0 (unreleased)
+
+Nothing yet. I don’t plan for there to be any real changes from 0.12.1;
+it should be just a bit of housecleaning and a version bump.
+
+# 0.12.1 (2017-01-20)
+
+- Remove superfluous Clone bound on Entry methods (#26)
+- Consistent application of `#[inline]` where it should be
+- Fix bad performance (see 724f94758def9f71ad27ff49e47e908a431c2728 for details)
+
+# 0.12.0 (2016-03-05)
+
+- Ungate `drain` iterator (stable from Rust 1.6.0)
+- Ungate efficient hashing (stable from Rust 1.7.0)
+- Remove `unstable` Cargo feature (in favour of a `bench` feature for benchmarking)
+
+# 0.11.2 (2016-01-22)
+
+- Rust warning updates only
+
+# 0.11.1 (2015-06-24)
+
+- Unstable Rust compatibility updates
+
+# 0.11.0 (2015-06-10)
+
+- Support concurrent maps (`Send + Sync` bound)
+- Rename `nightly` feature to `unstable`
+- Implement `Debug` for `Map` and `RawMap`
+- Replace `clone` Cargo feature with arcane DST magicks
+
+# Older releases (from the initial code on 2014-06-12 to 0.10.3 on 2015-04-18)
+
+I’m not giving a changelog for these artefacts of ancient history.
+If you really care you can look through the Git history easily enough.
+Most of the releases were just compensating for changes to the language
+(that being before Rust 1.0; yes, this crate has been around for a while).
+
+I do think that [`src/lib.rs` in the first commit] is a work of art,
+a thing of great beauty worth looking at; its simplicity is delightful,
+and it doesn’t even need to contain any unsafe code.
+
+[`src/lib.rs` in the first commit]: https://github.com/chris-morgan/anymap/tree/a294948f57dee47bb284d6a3ae1b8f61a902a03c/src/lib.rs