set ruby version to 1.9.3
some updates/explanations in the README
specify the coordinates column as :geographic, not :geometric, so that ST_DWithin(point, point, radius_meters) is calculated via spherical (like the actual US globe) distances
set time zone to Pacific
Since we only need to tell if a quake happend in the US or not, and the "place" property contains a US state in the descriptin, use this as a cheap hack to tell if a quake happend in the US
controller filtering on specified params
simplify for given requirements: sorting is implicit, avg magnitude all we are asked for
scope for pulling in average magnitude to a query