Readme: install command

adds uid_urlhash_idx on installation to support

without this Postgres will complain that "ERROR:  there is no unique or exclusion constraint matching the ON CONFLICT specification" with the following SQL,

INSERT INTO "upper_cache" ("urlHash", "url", "tags", "headers", "siteId", "dateCreated", "dateUpdated", "uid") VALUES ($1, $2, ARRAY[]::varchar[], $3, $4, $5, $6, $7) ON CONFLICT ("uid", "urlHash") DO UPDATE SET "urlHash"=$8, "url"=$9, "tags"=ARRAY[]::varchar[], "headers"=$10, "siteId"=$11, "dateCreated"=$12, "dateUpdated"=$13, "uid"=$14

composer version bump 1.6.0

1.6 Changelog

Prevent purge after resave entries

beta1

This is more than a patch release, version bump 1.4.0