How many releases did the DVD River Cottage forever have?
CREATE TABLE "dvd_releases" (
  "dvd_name" text,
  "released" text,
  "audio" text,
  "aspect_ratio" text,
  "duration" text,
  "number_of_episodes" real,
  "num_of_discs" real
);
SELECT COUNT("released") FROM "dvd_releases" WHERE "dvd_name"='River Cottage Forever';