@@ -0,0 +1,14 @@
+class InvitationMailerPreview < ActionMailer::Preview
+  def invitation
+    user = User.first
+    team = Team.first
+
+    invitation_id = Invitation.first_or_create(
+      email: 'user@example.com',
+      sender_id: user.id,
+      team_id: team.id,
+    )
+
+    InvitationMailer.invitation(invitation_id)
+  end
+end
Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping.