Replace all []*Foo by []Foo in sql db return values

- Implement SlicePtrsToSlice and use it in all `meddler.QueryAll` sql db functions to always return []Foo instead of []*Foo

db/utils_test.go

@@ -0,0 +1,35 @@
+package db
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type foo struct {
+	V int
+}
+
+func TestSliceToSlicePtrs(t *testing.T) {
+	n := 16
+	a := make([]foo, n)
+	for i := 0; i < n; i++ {
+		a[i] = foo{V: i}
+	}
+	b := SliceToSlicePtrs(a).([]*foo)
+	for i := 0; i < len(a); i++ {
+		assert.Equal(t, a[i], *b[i])
+	}
+}
+
+func TestSlicePtrsToSlice(t *testing.T) {
+	n := 16
+	a := make([]*foo, n)
+	for i := 0; i < n; i++ {
+		a[i] = &foo{V: i}
+	}
+	b := SlicePtrsToSlice(a).([]foo)
+	for i := 0; i < len(a); i++ {
+		assert.Equal(t, *a[i], b[i])
+	}
+}