Make schema choices based on reading available schemas.
Sketch of schema-upload functionality, not fully working yet.
Begin using registered datasources, requires entries in context.xml:

   <Resource name="jdbc/sqltutorDB" auth="Container"
        type="javax.sql.DataSource"
        maxActive="100" maxIdle="30" maxWait="10000"
        username="DB_Manager"
        password="<PASSWORD_HERE>"
        driverClassName="org.postgresql.Driver"
        url="jdbc:postgresql://localhost/sqltutor"/>

   <Resource name="jdbc/sqltutorUserDB" auth="Container"
        type="javax.sql.DataSource"
        maxActive="100" maxIdle="30" maxWait="10000"
        username="DB_Manager"
        password="<PASSWORD_HERE>"
        driverClassName="org.postgresql.Driver"
        url="jdbc:postgresql://localhost/sqltutorschemas"/>