Add instance_settings schema

lib/nulla/instance_settings.ex

@@ -0,0 +1,20 @@
+defmodule Nulla.InstanceSettings do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  schema "instance_settings" do
+    field :name, :string
+    field :description, :string
+    field :domain, :string
+    field :registration, :boolean, default: false
+    field :max_characters, :integer
+    field :max_upload_size, :integer
+  end
+
+  @doc false
+  def changeset(instance_settings, attrs) do
+    instance_settings
+    |> cast(attrs, [:name, :description, :domain, :registration, :max_characters, :max_upload_size])
+    |> validate_required([:name, :description, :domain, :registration, :max_characters, :max_upload_size])
+  end
+end

priv/repo/migrations/20250527054942_create_instance.exs

@@ -0,0 +1,14 @@
+defmodule Nulla.Repo.Migrations.CreateInstanceSettings do
+  use Ecto.Migration
+
+  def change do
+    create table(:instance_settings) do
+      add :name, :string, default: "Nulla", null: false
+      add :description, :string, default: "Freedom Social Network", null: false
+      add :domain, :string, default: "localhost", null: false
+      add :registration, :boolean, default: false, null: false
+      add :max_characters, :integer, default: 5000, null: false
+      add :max_upload_size, :integer, default: 50, null: false
+    end
+  end
+end