diff --git a/lib/bones73k/accounts/user.ex b/lib/bones73k/accounts/user.ex
index 6e69294..8d67ee0 100644
--- a/lib/bones73k/accounts/user.ex
+++ b/lib/bones73k/accounts/user.ex
@@ -16,6 +16,8 @@ defmodule Bones73k.Accounts.User do
   @max_password 80
 
   @derive {Inspect, except: [:password]}
+  @primary_key {:id, :binary_id, autogenerate: true}
+  @foreign_key_type :binary_id
   schema "users" do
     field :email, :string
     field :password, :string, virtual: true
diff --git a/lib/bones73k/accounts/user_token.ex b/lib/bones73k/accounts/user_token.ex
index ba3911e..7114f32 100644
--- a/lib/bones73k/accounts/user_token.ex
+++ b/lib/bones73k/accounts/user_token.ex
@@ -12,6 +12,8 @@ defmodule Bones73k.Accounts.UserToken do
   @change_email_validity_in_days 7
   @session_validity_in_days 60
 
+  @primary_key {:id, :binary_id, autogenerate: true}
+  @foreign_key_type :binary_id
   schema "users_tokens" do
     field :token, :binary
     field :context, :string
diff --git a/lib/bones73k/properties/property.ex b/lib/bones73k/properties/property.ex
index 6293542..97135e1 100644
--- a/lib/bones73k/properties/property.ex
+++ b/lib/bones73k/properties/property.ex
@@ -2,11 +2,13 @@ defmodule Bones73k.Properties.Property do
   use Ecto.Schema
   import Ecto.Changeset
 
+  @primary_key {:id, :binary_id, autogenerate: true}
+  @foreign_key_type :binary_id
   schema "properties" do
     field :description, :string
     field :name, :string
     field :price, :decimal
-    field :user_id, :id
+    belongs_to :user, Bones73k.Accounts.User
 
     timestamps()
   end
diff --git a/priv/repo/migrations/20200913000515_create_users_auth_tables.exs b/priv/repo/migrations/20200913000515_create_users_auth_tables.exs
index bdcc744..efc5f61 100644
--- a/priv/repo/migrations/20200913000515_create_users_auth_tables.exs
+++ b/priv/repo/migrations/20200913000515_create_users_auth_tables.exs
@@ -4,7 +4,8 @@ defmodule Bones73k.Repo.Migrations.CreateUsersAuthTables do
   def change do
     execute("CREATE EXTENSION IF NOT EXISTS citext", "")
 
-    create table(:users) do
+    create table(:users, primary_key: false) do
+      add(:id, :binary_id, primary_key: true)
       add(:email, :citext, null: false)
       add(:hashed_password, :string, null: false)
       add(:confirmed_at, :naive_datetime)
@@ -13,8 +14,9 @@ defmodule Bones73k.Repo.Migrations.CreateUsersAuthTables do
 
     create(unique_index(:users, [:email]))
 
-    create table(:users_tokens) do
-      add(:user_id, references(:users, on_delete: :delete_all), null: false)
+    create table(:users_tokens, primary_key: false) do
+      add(:id, :binary_id, primary_key: true)
+      add(:user_id, references(:users, type: :binary_id, on_delete: :delete_all), null: false)
       add(:token, :binary, null: false)
       add(:context, :string, null: false)
       add(:sent_to, :string)
diff --git a/priv/repo/migrations/20200914162043_create_properties.exs b/priv/repo/migrations/20200914162043_create_properties.exs
index 97f3ec0..d93506c 100644
--- a/priv/repo/migrations/20200914162043_create_properties.exs
+++ b/priv/repo/migrations/20200914162043_create_properties.exs
@@ -2,11 +2,12 @@ defmodule Bones73k.Repo.Migrations.CreateProperties do
   use Ecto.Migration
 
   def change do
-    create table(:properties) do
+    create table(:properties, primary_key: false) do
+      add(:id, :binary_id, primary_key: true)
       add(:name, :string)
       add(:price, :decimal)
       add(:description, :text)
-      add(:user_id, references(:users, on_delete: :nothing))
+      add(:user_id, references(:users, type: :binary_id, on_delete: :nothing))
 
       timestamps()
     end
diff --git a/priv/repo/seeds.exs b/priv/repo/seeds.exs
index 792cffa..72f4671 100644
--- a/priv/repo/seeds.exs
+++ b/priv/repo/seeds.exs
@@ -10,10 +10,10 @@
 # We recommend using the bang functions (`insert!`, `update!`
 # and so on) as they will fail if something goes wrong.
 
+import Ecto.Query
 alias Bones73k.Repo
 alias Bones73k.Accounts
 alias Bones73k.Accounts.User
-alias Bones73k.Properties
 alias Bones73k.Properties.Property
 
 ############################################################################
@@ -114,15 +114,18 @@ count_to_take = 123
 
 mock_props = props_json |> File.read!() |> Jason.decode!() |> Enum.take_random(count_to_take)
 
+random_user_query = from User, order_by: fragment("RANDOM()"), limit: 1
+
 mock_props =
   Enum.map(mock_props, fn e ->
     add_dt = NaiveDateTime.from_iso8601!(e["inserted_at"])
+    rand_user = Repo.one(random_user_query)
 
     %{
       name: e["name"],
       price: e["price"],
       description: e["description"],
-      user_id: e["user_id"],
+      user_id: rand_user.id,
       inserted_at: add_dt,
       updated_at: add_dt
     }