Update documentation in database.rb
Update documentation in database.rb

Allow Database#[] to take a block that is passed to fetch or from.
Refactor Database#fetch.

yazshel/sequel,reubano/sequel,gferguson-gd/sequel,seeARMS/sequel,beni55/sequel,offshore-safety/sequel,yazshel/sequel,knut2/sequel,pfarrell/sequel,nicohvi/sequel,offshore-safety/sequel,bigfix/sequel,freshpay/sequel,freshpay/sequel,uhoh-itsmaciek/sequel,dennis-d/custom_sequel,petergunz/sequel,t-morgan/sequel,mpalmer/sequel,seeARMS/sequel,nju520/sequel,offshore-safety/sequel,uhoh-itsmaciek/sequel,dennis-d/custom_sequel,t-morgan/sequel,mpalmer/sequel,pfarrell/sequel,nju520/sequel,beni55/sequel,davidbegin/sequel,nicohvi/sequel,davidbegin/sequel,Marketcircle/sequel,tmm1/sequel,chef/sequel,gferguson-gd/sequel,knut2/sequel,reubano/sequel