Query with multiples values for a field must be composed with AND

[everton]

Hi,

I saw your gem and the level it works is so great, really a good solution to integrate with SOLR.

I was experimenting it on a project where I need to do something like this:

query: { NAME: ['John', 'Castro']}

The resulting query was:

q=NAME%3AJohn+NAME%3ACastro

I expect something like:

q=NAME%3AJohn+AND+NAME%3ACastro

The patch is very small, but do you think I'm expecting it wrong? (I'm not an solr expert)