move contents of taskchampion repo to tc/

rust/taskchampion/src/macros.rs

@@ -0,0 +1,17 @@
+#![macro_use]
+
+/// Create a hashset, similar to vec!
+// NOTE: in Rust 1.56.0, this can be changed to HashSet::from([..])
+#[cfg(test)]
+macro_rules! set(
+    { $($key:expr),* $(,)? } => {
+        {
+            #[allow(unused_mut)]
+            let mut s = ::std::collections::HashSet::new();
+            $(
+                s.insert($key);
+            )*
+            s
+        }
+     };
+);