feat: organisations can also transfer time for the offer

Sergi says that an organisation can also give time for an offer from another organisation so now it also works if an admin chooses an organisation's account. I have also refactored my code a bit. Issue #638.

app/controllers/transfers_controller.rb

@@ -56,14 +56,15 @@ def find_source
 
   def create_persisters
     source_organization = @source.organization.account
+    source_type = @source.accountable_type
     destination_organization = @account.organization.account
-
+    @persisters = Array.new
     if source_organization == destination_organization
-      @persister = transfer_persister_between(@source, @account)
+      transfer_persister_between(@source, @account)
     else
-      @pers_src_org = transfer_persister_between(@source, source_organization)
-      @pers_between_orgs = transfer_persister_between(source_organization, destination_organization)
-      @pers_org_acc = transfer_persister_between(destination_organization, @account)
+      transfer_persister_between(@source, source_organization) if source_type == "Member"
+      transfer_persister_between(source_organization, destination_organization)
+      transfer_persister_between(destination_organization, @account)
     end
   end
 
@@ -72,19 +73,19 @@ def transfer_persister_between(source, destination)
       transfer_params.merge(source: source, destination: destination)
     )
 
-    ::Persister::TransferPersister.new(@transfer)
+    @persisters << ::Persister::TransferPersister.new(@transfer)
   end
 
   def persisters_saved?
-    @persister&.save || @pers_src_org&.save && @pers_between_orgs&.save && @pers_org_acc&.save
+    @persisters.each { |persister| return false if !persister.save }
   end
 
   def redirect_target
     case accountable = @account.accountable
     when Organization
       accountable
     when Member
-      accountable.organization == current_organization ? accountable.user : @source.accountable.user
+      accountable.organization == current_organization ? accountable.user : accountable.organization
     else
       raise ArgumentError
     end