Come up with a better topic storage system

[andrewthetechie]

Currently we use my hacky implementation on top of errbot's storage. This could be replaced by something much better. Consider using an orm that can use sqlite as well as other external databases.

It would be best to use sqlite, its already built-in into python and it provides easy sorting of information compared to other methods of storage. I used sqlite to store my user inputs and responses for a chat bot. And from looking at the code so far, it could easily be implemented as errbot's storage.

[andrewthetechie]

@Marcus-Mangru I'm open to any implementation as long as it sticks to a few things:

1. Awareness that this is an errbot plugin and first using errbot provided functions for things like storage, api access, pollers, etc before creating new code.
2. Awareness that this plugin may be run in many different environments. It could be run inside of a docker container with no persistent storage where the user wants to configure any backend to use an external service. I.e. if you use a database, be sure it can be configured to use an external database server or the user can configure the path for the sqlite db.