Compatibility with phoenix_pubsub 2.0.0

lib/pleroma/application.ex

@@ -202,7 +202,10 @@ defmodule Pleroma.Application do
   end
 
   defp chat_child(true) do
-    [Pleroma.Web.ChatChannel.ChatChannelState]
+    [
+      Pleroma.Web.ChatChannel.ChatChannelState,
+      {Phoenix.PubSub, [name: Pleroma.PubSub, adapter: Phoenix.PubSub.PG2]}
+    ]
   end
 
   defp chat_child(_), do: []

lib/pleroma/web/web.ex

@@ -177,7 +177,7 @@ defmodule Pleroma.Web do
   def channel do
     quote do
       # credo:disable-for-next-line Credo.Check.Consistency.MultiAliasImportRequireUse
-      use Phoenix.Channel
+      import Phoenix.Channel
       import Pleroma.Web.Gettext
     end
   end

test/support/channel_case.ex

@@ -22,7 +22,7 @@ defmodule Pleroma.Web.ChannelCase do
   using do
     quote do
       # Import conveniences for testing with channels
-      use Phoenix.ChannelTest
+      import Phoenix.ChannelTest
       use Pleroma.Tests.Helpers
 
       # The default endpoint for testing