Use gateways in mattermost config instead of samechannelgateway

Matrix wants a special format for the channel name, so
samechannelgateway doesn't work.

nixos_configs/bridge.nix

@@ -38,6 +38,53 @@ in {
   ];
 
   services.matterbridge = let
+
+    channels = [
+      "a-rusty-venture"
+      "anime"
+      "bossin_around"
+      "bot-test"
+      "bridge-test"
+      "cryptic-bunker"
+      "cryptic-chat"
+      "cryptic-net-public"
+      "dumbathon"
+      "europe"
+      "generic-gaming"
+      "get-rich-fast"
+      "gnv"
+      "golang"
+      "jerbs"
+      "main_linux"
+      "minecraft"
+      "nyc"
+      "omg-berks"
+      "sf"
+      "smersh"
+      "to-the-moon-and-back"
+      "travel"
+      "tunes"
+    ];
+
+  gateways = lib.strings.concatMapStrings (channel: ''
+    [[gateway]]
+    name="${channel}-gateway"
+    enable=true
+
+    [[gateway.inout]]
+    account="matrix.wafflefarm"
+    channel="#${channel}:waffle.farm"
+
+    [[gateway.inout]]
+    account="slack.cryptic"
+    channel="${channel}"
+
+    [[gateway.inout]]
+    account="discord.cryptic"
+    channel="${channel}"
+
+  '') channels;
+
   config-file = pkgs.writeText "matterbridge.toml" ''
 [discord.cryptic]
 Token="${secrets.matterbridge.discord2.token}"
@@ -60,51 +107,7 @@ SpoofUsername=true
 PreserveThreading=true
 KeepQuotedReply=false
 
-[[gateway]]
+${gateways}
-name="testgateway"
-enable=true
-
-[[gateway.inout]]
-account="matrix.wafflefarm"
-channel="#bridge-test:waffle.farm"
-
-[[gateway.inout]]
-account="slack.cryptic"
-channel="bridge-test"
-
-[[gateway.inout]]
-account="discord.cryptic"
-channel="bridge-test"
-
-[[samechannelgateway]]
-   name="same-channel-gw"
-   enable = true
-   accounts = [ "slack.cryptic", "discord.cryptic" ]
-   channels = [
-    "a-rusty-venture",
-    "anime",
-    "bossin_around",
-    "bot-test",
-    "cryptic-bunker",
-    "cryptic-chat",
-    "cryptic-net-public",
-    "dumbathon",
-    "europe",
-    "generic-gaming",
-    "get-rich-fast",
-    "gnv",
-    "golang",
-    "jerbs",
-    "main_linux",
-    "minecraft",
-    "nyc",
-    "omg-berks",
-    "sf",
-    "smersh",
-    "to-the-moon-and-back",
-    "travel",
-    "tunes"
-   ]
     '';
   in {
     enable = true;