setter foreign_key initial design

README.md

@@ -152,13 +152,23 @@ When you run PaperTrail.insert/1 transaction, insert_version_id and current_vers
 
 When you update a model, current_version_id gets updated during the transaction. Example:
 
-** remove wrong Elixir compiler errors
+## Storing setter relationships
+You could specify setter relationship to `paper_trail` versions. This is doable by specifying `:setter` keyword list for your application:
+
+```elixir
+  config :paper_trail, setter: [name: :user, model: YourApp.User]
+  # For most application setter will be user, models can be updated/created/deleted by several users.
+```
+
 
-** explain the columns
 
 ## Storing version meta data
 Your versions don't need a model lifecycle callbacks like before_create or before_update for any extra meta data, all your meta data could be stored in one object and that object could be passed as the second optional parameter to PaperTrail.insert || PaperTrail.update || PaperTrail.delete :
 
 ## Suggestions
 - PaperTrail.Version(s) order matter,
 - don't delete your paper_trail versions, instead you can merge them
+
+## TODO
+** remove wrong Elixir compiler errors
+** explain the columns

lib/mix/tasks/papertrail/install.ex

@@ -22,22 +22,24 @@ defmodule Mix.Tasks.Papertrail.Install do
           add :item_type,    :string, null: false
           add :item_id,      :integer
           add :item_changes, :map, null: false
-          #{created_by_field()}
+          add :setter_id, :integer
+          #{set_by_field()}
           add :meta,         :map
 
           add :inserted_at,  :utc_datetime, null: false
         end
 
+        create index(:versions, [:setter_id])
+        create index(:versions, [:item_id, :item_type])
         # Uncomment if you want to add the following indexes to speed up special queries:
-        # create index(:versions, [:item_id, :item_type])
         # create index(:versions, [:event, :item_type])
         # create index(:versions, [:item_type, :inserted_at])
       end
     end
     """
   end
 
-  defp created_by_field do
+  defp set_by_field do
     case @strict_mode do
       true -> "add :set_by, :string, size: 50, null: false, default: 'unknown'"
       _ -> "add :set_by, :string, size: 50"

lib/paper_trail/repo_client.ex

@@ -4,5 +4,6 @@ defmodule PaperTrail.RepoClient do
   Gets the configured repo module or defaults to Repo if none configured
   """
   def repo, do: Application.get_env(:paper_trail, :repo) || Repo
+  def setter, do: Application.get_env(:paper_trail, :setter) || nil
   def strict_mode, do: Application.get_env(:paper_trail, :strict_mode) || false
 end

lib/version.ex

@@ -4,22 +4,27 @@ defmodule PaperTrail.Version do
   import Ecto.Changeset
   import Ecto.Query
 
+  @setter PaperTrail.OriginatorClient.setter
+
   schema "versions" do
     field :event, :string
     field :item_type, :string
     field :item_id, :integer
     field :item_changes, :map
     field :set_by,   :string
     field :meta, :map
+    field :setter_id, :integer
 
-    # belongs_to :setter
+    if @setter do
+      belongs_to @setter[:name], @setter[:model], foreign_key: :originator_id, define_field: false
+    end
 
     timestamps(updated_at: false)
   end
 
   def changeset(model, params \\ :empty) do
     model
-    |> cast(params, [:item_type, :item_id, :item_changes, :set_by, :meta])
+    |> cast(params, [:item_type, :item_id, :item_changes, :set_by, :setter_id, :meta])
     |> validate_required([:event, :item_type, :item_id, :item_changes])
   end