Add /join command

telegram/commands.go

@@ -356,6 +356,18 @@ func (c *Client) ProcessChatCommand(chatID int64, cmdline string) (string, bool)
 			gateway.SPFrom(strconv.FormatInt(chat.Id, 10)),
 			gateway.SPType("subscribe"),
 		)
+	// join https://t.me/publichat
+	case "join":
+		if len(args) < 1 {
+			return notEnoughArguments, true
+		}
+
+		_, err := c.client.JoinChatByInviteLink(&client.JoinChatByInviteLinkRequest{
+			InviteLink: args[0],
+		})
+		if err != nil {
+			return err.Error(), true
+		}
 	case "help":
 		return helpString(helpTypeChat), true
 	default: