Update dbquery docs

[dkirkby]

PR #5 replaces mssql with sqlalchemy, so this changes the instructions for running dbquery. Note that sqlalchemy is included with anaconda.

[dkirkby]

@alexabate I just noticed that you used host="localhost" when you updated dbquery to use sqlalchemy (see here) Is that because you were already logged on to the server at UW?

[alexabate]

Yes I believe so. I think I logged in to UW in another terminal window