Add pagination by max_id instead of offset/limit

app/models/feed.rb

@@ -4,12 +4,12 @@ class Feed
     @account = account
   end
 
-  def get(limit, offset = 0)
-    unhydrated = redis.zrevrange(key, offset, limit)
+  def get(limit, max_id = '+inf')
+    unhydrated = redis.zrevrangebyscore(key, "(#{max_id}", '-inf', limit: [0, limit])
     status_map = Hash.new
 
     # If we're after most recent items and none are there, we need to precompute the feed
-    return PrecomputeFeedService.new.(@type, @account).take(limit) if unhydrated.empty? && offset == 0
+    return PrecomputeFeedService.new.(@type, @account).take(limit) if unhydrated.empty? && max_id == '+inf'
 
     Status.where(id: unhydrated).with_includes.with_counters.each { |status| status_map[status.id.to_s] = status }
     return unhydrated.map { |id| status_map[id] }.compact