Storing state in sessions

1. What does it mean for an application to be multi-tenant?
Tenant is like someone one that lives in a house and we want to build a house that has many tenants, that has access to all
the things in the house but it's own separate room.  They can all use things like the bathroom and kitchen and share those things together.

2. Why would you want to build an application to be multi-tenant?
You can do work for multiple clients and charge them all by just building one app!

3. How do you implement multi-tenancy at the data / database level?
Have different tables for different 'stores'

4. How do Active Record scopes help keep tenant data segregated?
Rails Magick!

5. Why is multi-tenancy dangerous from a security/privacy perspective?
Cause you don't want a user of one store having access to another stores data.