Improve progress updating, fix warnings

Caps/Preview Content/Database+Mock.swift

@@ -0,0 +1,32 @@
+import UIKit
+
+extension Database {
+
+    static var mock: Database {
+        let caps = [
+            Cap(id: 123, name: "My new cap"),
+            Cap(id: 234, name: "My favorite cap"),
+            Cap(id: 345, name: "My oldest cap"),
+            Cap(id: 456, name: "My new cap"),
+            Cap(id: 567, name: "My favorite cap"),
+            Cap(id: 678, name: "My oldest cap"),
+        ].reduce(into: [:]) { $0[$1.id] = $1 }
+
+        let db = Database(caps: caps)
+        db.serverPath = "https://caps.christophhagen.de"
+
+        db.image = UIImage(systemSymbol: .photo)
+        return db
+    }
+
+    static var largeMock: Database {
+        let caps = (1..<500)
+            .map { Cap(id: $0, name: "Cap \($0)") }
+            .reduce(into: [:]) { $0[$1.id] = $1 }
+
+        let db = Database(caps: caps)
+        db.serverPath = "https://caps.christophhagen.de"
+        db.image = UIImage(systemSymbol: .photo)
+        return db
+    }
+}