Add post permalinks (#8)

Reviewed-on: #8
Co-authored-by: codegirl-007 <s.raide@gmail.com>

internal/web/posts_test.go

@@ -462,6 +462,9 @@ func TestQuestionPageRendersNestedPostControls(t *testing.T) {
 		`data-submit-button`,
 		`action="/posts/` + root.ID + `/edit"`,
 		`action="/posts/` + homeownerReply.ID + `/edit"`,
+		`href="/questions/` + root.ID + `#post-` + root.ID + `"`,
+		`href="/questions/` + root.ID + `#post-` + homeownerReply.ID + `"`,
+		`href="/questions/` + root.ID + `#post-` + adminReply.ID + `"`,
 		`>The model number is 123A.</textarea>`,
 		`removeAttribute('open')`,
 	} {
@@ -469,6 +472,9 @@ func TestQuestionPageRendersNestedPostControls(t *testing.T) {
 			t.Fatalf("question page missing %q: %s", want, body)
 		}
 	}
+	if got := strings.Count(body, ">Permalink</a>"); got != 3 {
+		t.Fatalf("question page rendered %d permalinks, want 3: %s", got, body)
+	}
 	if strings.Contains(body, `action="/posts/`+adminReply.ID+`/edit"`) {
 		t.Fatalf("homeowner can edit admin reply: %s", body)
 	}