Rails: Upgrading a Legacy Rails App Part 3
We finalize the upgrade process by patching up a few files. Once all the changes are in place we should be able to run
bundle update rails
This will upgrade our rails app to the latest version with all the dependencies.
We can then just launch the application with rails s and it should launch the application using puma.
Parting thoughts on Upgrading Rails
At this point having a test suite can be extremely useful. Once you upgrade the only way to make sure your entire app is working and nothing broke (or if it did quickly fix it) is to have a test suite. This is one of the major reasons why we should write tests for our application, and in future episodes we will cover testing in depth.
You can review the pull request for the upgrade here.