*Reorganized code so that further expansion is possible in a very organized manner.

*modpol.add_member() -- added a check if the member is already a member of that organized

*storage -- fixed bug by moving storageref to top of file

*added on_joinplayer to add players to instance

*moved minetest specific code in init.lua to modpol_minetest, organized in folders.
All overrides in one folder, all chatcommands in another, the on_joinplayer in modpol_minetest/orgs/instance.lua

storage/storage-local.lua

@@ -0,0 +1,117 @@
+-- ===================================================================
+-- /storage-local.lua
+-- Persistent storage in /data using Serpent Serializer
+-- Unix systems only
+
+-- ===================================================================
+-- Set directories and filenames
+
+modpol.datadir     = modpol.topdir  .. "/data"
+modpol.file_ledger = modpol.datadir .. "/ledger.dat"
+modpol.file_orgs   = modpol.datadir .. "/orgs.dat"
+
+os.execute ("mkdir -p " .. modpol.datadir)
+
+modpol.ocutil.setlogdir  (modpol.datadir)
+modpol.ocutil.setlogname ("modpol.log")
+
+-- ===================================================================
+-- Set up the Serpent Serializer functions.
+
+modpol.serpent = {}
+dofile (modpol.topdir .. "/util/serpent/serpent.lua")
+
+-- ===================================================================
+-- This function stores "ledger" data to disk.
+
+local store_ledger = function()
+    local ok =  modpol.ocutil.file_write (modpol.file_ledger,
+modpol.serpent.dump (modpol.ledger))
+
+    if    ok ~= true then
+        modpol.ocutil.fatal_error ("store_data: ledger")
+    end
+
+    local nn  = modpol.ocutil.table_length (modpol.ledger)
+    local str = "entries"
+    if nn == 1 then str = "entry" end
+    modpol.ocutil.log (nn .. " global ledger entries stored to disk")
+end
+
+-- ===================================================================
+-- This function stores "orgs" data to disk.
+
+local store_orgs = function()
+    local ok =  modpol.ocutil.file_write (modpol.file_orgs,
+modpol.serpent.dump (modpol.orgs))
+
+    if    ok ~= true then
+        modpol.ocutil.fatal_error ("store_data: orgs")
+    end
+
+    local nn  = modpol.ocutil.table_length (modpol.orgs)
+    local str = "entries"
+    if nn == 1 then str = "entry" end
+    modpol.ocutil.log (nn .. " orgs stored to disk")
+end
+
+-- ===================================================================
+-- This function stores data to disk.
+
+modpol.store_data = function()
+    store_ledger()
+    store_orgs()
+end
+
+-- ===================================================================
+-- This function loads "ledger" data from disk.
+
+local load_ledger = function()
+    local obj =  modpol.ocutil.file_read (modpol.file_ledger )
+    if    obj ~= nil then
+        local func, err = load (obj)
+        if err then
+            modpol.ocutil.fatal_error ("load_data: ledger"   )
+        end
+        modpol.ledger = func()
+
+        local nn  = modpol.ocutil.table_length (modpol.ledger)
+        local str = "entries"
+        if nn == 1 then str = "entry" end
+        modpol.ocutil.log (nn .. " global ledger entries loaded from disk")
+    else
+        modpol.ocutil.log ("No stored global ledger data found")
+    end
+end
+
+-- ===================================================================
+-- This function loads "orgs" data from disk.
+
+local load_orgs   = function()
+    local obj =  modpol.ocutil.file_read (modpol.file_orgs )
+    if    obj ~= nil then
+        local func, err = load (obj)
+        if err then
+            modpol.ocutil.fatal_error ("load_data: orgs"   )
+        end
+        modpol.orgs = func()
+
+        local nn  = modpol.ocutil.table_length (modpol.orgs)
+        local str = "entries"
+        if nn == 1 then str = "entry" end
+        modpol.ocutil.log (nn .. " orgs loaded from disk")
+    else
+        modpol.ocutil.log ("No stored orgs data found")
+    end
+end
+
+-- ===================================================================
+-- This function loads stored data from disk.
+
+modpol.load_storage = function()
+    load_ledger()
+    load_orgs()
+end
+
+-- ===================================================================
+-- End of file.

storage/storage-mod_storage.lua

@@ -0,0 +1,34 @@
+-- ===================================================================
+-- /storage-mod_storage.lua
+-- Persistent storage via Minetest's mod_storage method
+-- See https://dev.minetest.net/StorageRef
+
+-- Loads content of stored orgs and ledger from mod_storage
+
+
+--get modstorageref
+local mod_storage = minetest.get_mod_storage()
+
+
+
+modpol.load_storage = function()
+   
+   -- load orgs
+   local stored_orgs = minetest.deserialize(mod_storage:get_string("orgs"))
+   if (stored_orgs ~= nil) then
+      modpol.orgs = stored_orgs
+   end
+   -- load orgs
+   local stored_ledger = minetest.deserialize(mod_storage:get_string("ledger"))
+   if (stored_ledger ~= nil) then
+      modpol.ledger = stored_ledger
+   end
+end
+
+-- Stores content of current orgs and ledger to mod_storage
+modpol.store_data = function()
+
+   -- write to storage
+   mod_storage:set_string("orgs", minetest.serialize(modpol.orgs))
+   mod_storage:set_string("ledger", minetest.serialize(modpol.ledger))
+end