posts: fix exception when post has source like 'https://www.twitter.com/username'.

`twitter.com` sources worked but `www.twitter.com` didn't.

Also match the URL by class instead of by site name to ensure we match
the expected class.

app/logical/source/url/twitter.rb

@@ -29,7 +29,8 @@ class Source::URL::Twitter < Source::URL
   attr_reader :status_id, :twitter_username, :user_id
 
   def self.match?(url)
-    url.host.in?(%w[twitter.com mobile.twitter.com pic.twitter.com pbs.twimg.com video.twimg.com t.co])
+    return false if Source::URL::TwitPic.match?(url) # TwitPic uses https://o.twimg.com/ URLs
+    url.domain.in?(%w[twitter.com twimg.com t.co])
   end
 
   def parse

app/logical/sources/strategies/foundation.rb

@@ -5,7 +5,7 @@ module Sources
   module Strategies
     class Foundation < Base
       def match?
-        parsed_url&.site_name == "Foundation"
+        Source::URL::Foundation === parsed_url
       end
 
       def image_urls

app/logical/sources/strategies/hentai_foundry.rb

@@ -5,7 +5,7 @@ module Sources
   module Strategies
     class HentaiFoundry < Base
       def match?
-        parsed_url&.site_name == "Hentai Foundry"
+        Source::URL::HentaiFoundry === parsed_url
       end
 
       def image_urls

app/logical/sources/strategies/lofter.rb

@@ -5,7 +5,7 @@ module Sources
   module Strategies
     class Lofter < Base
       def match?
-        parsed_url&.site_name == "Lofter"
+        Source::URL::Lofter === parsed_url
       end
 
       def image_urls

app/logical/sources/strategies/newgrounds.rb

@@ -5,7 +5,7 @@ module Sources
   module Strategies
     class Newgrounds < Base
       def match?
-        parsed_url&.site_name == "Newgrounds"
+        Source::URL::Newgrounds === parsed_url
       end
 
       def image_urls

app/logical/sources/strategies/skeb.rb

@@ -5,7 +5,7 @@ module Sources
   module Strategies
     class Skeb < Base
       def match?
-        parsed_url&.site_name == "Skeb"
+        Source::URL::Skeb === parsed_url
       end
 
       def image_urls

app/logical/sources/strategies/twit_pic.rb

@@ -4,7 +4,7 @@
 module Sources::Strategies
   class TwitPic < Base
     def match?
-      parsed_url&.site_name == "TwitPic"
+      Source::URL::TwitPic === parsed_url
     end
 
     def normalize_for_source

app/logical/sources/strategies/twitter.rb

@@ -24,7 +24,7 @@ module Sources::Strategies
     end
 
     def match?
-      parsed_url&.site_name == "Twitter"
+      Source::URL::Twitter === parsed_url
     end
 
     def image_urls

test/unit/sources/twitter_test.rb

@@ -302,6 +302,7 @@ module Sources
         assert_equal(source2, Sources::Strategies.normalize_source(source2))
         assert_equal(source2, Sources::Strategies.normalize_source(source3))
         assert_equal(source2, Sources::Strategies.normalize_source(source4))
+        assert_equal("https://www.twitter.com/irt_5433", Sources::Strategies.normalize_source("https://www.twitter.com/irt_5433"))
       end
     end
   end