built basic ui structure in /hierarchy

river_connect/priv/repo/migrations/20260214234844_create_hierarchy.exs

@@ -0,0 +1,43 @@
+defmodule RiverConnect.Repo.Migrations.CreateHierarchy do
+  use Ecto.Migration
+
+  def change do
+    create table(:springs) do
+      add :name, :string, null: false
+      # :dm, :job, :custom
+      add :type, :string, null: false
+      add :description, :text
+
+      timestamps()
+    end
+
+    create table(:rivers) do
+      add :name, :string, null: false
+      add :description, :text
+      add :spring_id, references(:springs, on_delete: :delete_all), null: false
+
+      timestamps()
+    end
+
+    create index(:rivers, [:spring_id])
+
+    create table(:streams) do
+      add :name, :string, null: false
+      add :topic, :string
+      add :river_id, references(:rivers, on_delete: :delete_all), null: false
+
+      timestamps()
+    end
+
+    create index(:streams, [:river_id])
+
+    create table(:trenches) do
+      add :name, :string
+      add :stream_id, references(:streams, on_delete: :delete_all), null: false
+
+      timestamps()
+    end
+
+    create index(:trenches, [:stream_id])
+  end
+end