Make sure we have the correct index and index sizes for some columns.
Make sure we have the correct index and index sizes for some columns.

mysql makes it hard to make indexes on long text columns

these should actually just index the first few characters, which
i'll do in a later cleanup, and preserve the length of the cols.

tiddlyweb/tiddlywebplugins.sqlalchemy,tiddlyweb/tiddlywebplugins.sqlalchemy