ellos harvester

Signed-off-by: zeljko <zeljko@zwr.fi>
mongoid sorting solution

This was a major issue. Mongoid always sorts by 'primery key' even
if no sort is given, and MongoDB does not index that 'primary key',
which is anyhow just another field. This causes huge delays.

Two solutions /both employed here, although they make the other
redundant/ are:

1. Explicitely sort by some field that is indexed.
2. Always index the primary key (_id) field.

Signed-off-by: zeljko <zeljko@zwr.fi>
tag getting

This changes contains meat needed to get all the words from the titles
of products, which will either become tags, synonyms or ignored.

Signed-off-by: zeljko <zeljko@zwr.fi>
scanner speedup

Signed-off-by: zeljko <zeljko@zwr.fi>
improved tags grabbing

Signed-off-by: zeljko <zeljko@zwr.fi>