Add more metrics

Sources/App/Extensions/Sequence+Extensions.swift

@@ -0,0 +1,12 @@
+import Foundation
+
+extension Sequence {
+
+    func count(where isIncluded: (Element) -> Bool) -> Int {
+        reduce(0) { isIncluded($1) ? $0 + 1 : $0 }
+    }
+    
+    func sum(converting: (Element) -> Int) -> Int {
+        reduce(0) { $0 + converting($1) }
+    }
+}