mail: Read mails to roll up from external file

Changed rollup filter to read the files to be rolled up from 'rollup.txt'
file in the imapfilter configuration directory. (by default in XDG
basedir-compliant directory such as '~/.config/imapfilter/rollup.txt')

The file consists of sender addresses with a single address on each
line.

mail/.config/imapfilter/filters/rollup-dump.lua

@@ -1,35 +1,27 @@
 function sendToFolder(folderFrom, folderTo, senders)
-
   for _, sender in pairs(senders) do
     messages = folderFrom:contain_from(sender)
     messages:mark_seen()
     messages:move_messages(folderTo)
   end
-
 end
 
-for _, acc in pairs(accounts) do
-  sendToFolder ( acc["Inbox"], acc["Dump"],
-    {
-    "news@todoist.com",
-    "server@email.woommart.com",
-    "noreply@medium.com",
-    "rollup@unroll.me",
-    "team@readdlenews.com",
-    "info@netdata.cloud",
-    "taco@trello.com",
-    "quincy@freecodecamp.org",
-    "support@instapaper.com",
-    "update@author.email.elsevier.com",
-    "newsletter@cloudflare.com",
-    "noreply@notify.docker.com",
-    "hello@skillshare.com",
-    "noreply@hostelworld.com",
-    "waitlist@isthereanydeal.com",
-    "info@mynameisgriz.com",
-    "news@postman.com",
-    "no-reply@tumblr.com",
-    "contact@mailer.humblebundle.com",
-    "info@audible.de"
-  })
+function getSenderList(file)
+  local rollupSenders={}
+
+  local file = io.open(file)
+  if file then
+    for line in file:lines() do
+      table.insert(rollupSenders, line)
+    end
+  else
+    print("ERROR: rollup did not find rollup.txt file containing mail addresses.")
+  end
+  return rollupSenders
 end
+
+sendToFolder (
+  accounts.gmail["Inbox"],
+  accounts.gmail["Dump"],
+  getSenderList(getConfigDir() .. "/rollup.txt")
+  )