Security tasks

I updated the session key to be outside of version control. I also had to make some other unrelated changes though in order for the app to be able to `bundle install` and to run, due to some changes that have been made in the codebase but haven't been updated in the bootstrap code to run the app.

The session key has been updated in the code, but still needs to be deployed to the server. When deploying to the server, make sure to add the following ENV config variables. But first, generate a new secret token for the server by running this Rails task (can be run locally and just copy/paste the output to the ENV variable on the server):

```
rake secret
```

```
RAILS_TOKEN=gradecraft
RAILS_SECRET=[output of rake secret]
```