Making progress.

src/item.rs

@@ -0,0 +1,11 @@
+use crate::fitter::Fitter;
+
+pub struct Item {
+    pub fitter: Box<dyn Fitter>,
+}
+
+impl Item {
+    pub fn new(fitter: Box<dyn Fitter>) -> Self {
+        Item { fitter }
+    }
+}