How can I prevent myself as a developer from seeing user-submitted data on the server?

I run a website where users submit confidential information. For the sake of example, let's say it's a website for users to store their deepest and darkest secrets.

Protecting this data and keeping it private is important to me. I'm using HTTPS, encrypting the data in the database, have long passwords and two factor authentication on my accounts, etc.

Last week, I was having some production issues and needed to view server log output to see what requests the server was receiving, and generally, what was going on. It's hosted on Heroku which has some tools, like Papertrail, that make it easy to view server logs. The problem is that the web server is receiving user-submitted form input which appears in the server output (as a params hash that was received from the form submission).

So here I am, trying to blur my vision so I don't read someone's private information while trying to track down the problem. Is there any way to obscure this data when it's received by the server?

One of the questions I receive when people hear about the website is, "Well, how do I know you're not just reading my secrets?" The truth is, as far as I know, if an admin with access to the server wants to read any of this data, there's really nothing stopping them. I'd like to be able to say, "Nobody can view your secrets. Not even I, ha HA!"

Is this reasonable or even possible?

Note: this is a Ruby on Rails 5 app, hosted on Heroku, using Postgres.