Stash rating system (#2830)

* add rating100 fields to represent rating range 1-100
* deprecate existing (1-5) rating fields
* add half- and quarter-star options for rating system
* add decimal rating system option

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

pkg/models/rating_test.go

@@ -0,0 +1,55 @@
+package models
+
+import (
+	"testing"
+)
+
+func TestRating100To5(t *testing.T) {
+	tests := []struct {
+		name      string
+		rating100 int
+		want      int
+	}{
+		{"20", 20, 1},
+		{"100", 100, 5},
+		{"1", 1, 1},
+		{"10", 10, 1},
+		{"11", 11, 1},
+		{"21", 21, 1},
+		{"31", 31, 2},
+		{"0", 0, 1},
+		{"-100", -100, 1},
+		{"120", 120, 5},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Rating100To5(tt.rating100); got != tt.want {
+				t.Errorf("Rating100To5() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRating5To100(t *testing.T) {
+	tests := []struct {
+		name    string
+		rating5 int
+		want    int
+	}{
+		{"1", 1, 20},
+		{"5", 5, 100},
+		{"2", 2, 40},
+		{"3", 3, 60},
+		{"4", 4, 80},
+		{"6", 6, 100},
+		{"0", 0, 20},
+		{"-1", -1, 20},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Rating5To100(tt.rating5); got != tt.want {
+				t.Errorf("Rating5To100() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}