http://blog.sefindustries.com/a-really-simple-slack-to-trello-integration/
Assuming that you have the Google App Engine SDK properly installed, Go setup, and you've checked out this app into the correct path (src/github.com/your-name/slack-to-trello)
How to Use:
Step 1: Fill Out Your app.json
Copy sample_config.json to app.json
As described in the blog post, paste in your required information
Step 2: Fill out your app.yaml
Just get the project name from Google App Engine and paste it in (sample is sample.yaml)
Step 3: goapp deploy