Make matching specific search fields more valuable than others

[blakesweeney]

If a user enters the name of a gene (e.g. XIST) we should put a high weight on all results that have that exact string in the gene field. Consider searching for XIST (http://rnacentral.org/search?q=XIST) where the first hit is XIST antisense but the second has XIST in the gene field. XIST should be first because the result has XIST in the gene field. Hopefully we can consider what field matches as part of sorting hits. This may require changes in how things are indexed as well.