Merge pull request #1 from Cricycle/chelsea

A bunch of things Chelsea worked on over break
Some of Alex's SQL

Creates data when you run sample_data (if appropriate tables exist)
TODO: update sample_data.sql to create tables if they don't exist.

Function ranks photos by votes, users by votes.

Create the votes table.

Truncate query created for the votes table, but it doesn't run
automatically.
Forgot to save
SQL statements for assignment 3
SQL statements for assignment 3
Fixed photos table to have indexing.
Fixed photos table to have indexing.
Added test data