multi_db.patch

diff --git c/Gemfile w/Gemfile
index c96f2d6..9fae90d 100644
--- c/Gemfile
+++ w/Gemfile
@@ -6,7 +6,7 @@ ruby '2.7.0'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 6.1.1'
 # Use sqlite3 as the database for Active Record
-gem 'sqlite3', '~> 1.4'
+gem 'mysql2'
 # Use Puma as the app server
 gem 'puma', '~> 5.0'
 # Use SCSS for stylesheets
diff --git c/Gemfile.lock w/Gemfile.lock
index f138bbb..31ebeaa 100644
--- c/Gemfile.lock
+++ w/Gemfile.lock
@@ -101,6 +101,7 @@ GEM
     mini_mime (1.0.2)
     minitest (5.14.3)
     msgpack (1.4.2)
+    mysql2 (0.5.3)
     nio4r (2.5.4)
     nokogiri (1.11.1-x86_64-linux)
       racc (~> 1.4)
@@ -169,7 +170,6 @@ GEM
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
-    sqlite3 (1.4.2)
     thor (1.1.0)
     tilt (2.0.10)
     turbolinks (5.2.1)
@@ -199,6 +199,7 @@ GEM
     zeitwerk (2.4.2)
 
 PLATFORMS
+  ruby
   x86_64-linux
 
 DEPENDENCIES
@@ -207,13 +208,13 @@ DEPENDENCIES
   capybara (>= 3.26)
   jbuilder (~> 2.7)
   listen (~> 3.3)
+  mysql2
   puma (~> 5.0)
   rack-mini-profiler (~> 2.0)
   rails (~> 6.1.1)
   sass-rails (>= 6)
   selenium-webdriver
   spring
-  sqlite3 (~> 1.4)
   turbolinks (~> 5)
   tzinfo-data
   web-console (>= 4.1.0)
diff --git c/app/models/product.rb w/app/models/product.rb
new file mode 100644
index 0000000..2b2ac32
--- /dev/null
+++ w/app/models/product.rb
@@ -0,0 +1,2 @@
+class Product < ShardedRecord
+end
diff --git c/app/models/sharded_record.rb w/app/models/sharded_record.rb
new file mode 100644
index 0000000..11f83fa
--- /dev/null
+++ w/app/models/sharded_record.rb
@@ -0,0 +1,5 @@
+class ShardedRecord < ApplicationRecord
+  self.abstract_class = true
+
+  connects_to database: { writing: :sharded }
+end
diff --git c/config/database.yml w/config/database.yml
index 4a8a1b2..8265560 100644
--- c/config/database.yml
+++ w/config/database.yml
@@ -1,25 +1,39 @@
-# SQLite. Versions 3.8.0 and up are supported.
-#   gem install sqlite3
-#
-#   Ensure the SQLite 3 gem is defined in your Gemfile
-#   gem 'sqlite3'
-#
 default: &default
-  adapter: sqlite3
+  adapter: mysql2
   pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
   timeout: 5000
+  host: 127.0.0.1
+  port: 2225
+  username: vt
+  password:
+  encoding: utf8
 
 development:
-  <<: *default
-  database: db/development.sqlite3
+  primary:
+    <<: *default
+    database: unsharded
+  sharded:
+    <<: *default
+    database: sharded
+    migrations_paths: "db/migrate_sharded"
 
 # Warning: The database defined as "test" will be erased and
 # re-generated from your development database when you run "rake".
 # Do not set this db to the same as development or production.
 test:
-  <<: *default
-  database: db/test.sqlite3
+  primary:
+    <<: *default
+    database: unsharded
+  sharded:
+    <<: *default
+    database: sharded
+    migrations_paths: "db/migrate_sharded"
 
 production:
-  <<: *default
-  database: db/production.sqlite3
+  primary:
+    <<: *default
+    database: unsharded
+  sharded:
+    <<: *default
+    database: sharded
+    migrations_paths: "db/migrate_sharded"
diff --git c/db/migrate_sharded/20210210182604_create_products.rb w/db/migrate_sharded/20210210182604_create_products.rb
new file mode 100644
index 0000000..9eae46a
--- /dev/null
+++ w/db/migrate_sharded/20210210182604_create_products.rb
@@ -0,0 +1,9 @@
+class CreateProducts < ActiveRecord::Migration[6.1]
+  def change
+    create_table :products do |t|
+      t.string :name
+
+      t.timestamps
+    end
+  end
+end
diff --git c/db/schema.rb w/db/schema.rb
new file mode 100644
index 0000000..77bcf0f
--- /dev/null
+++ w/db/schema.rb
@@ -0,0 +1,15 @@
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# This file is the source Rails uses to define your schema when running `bin/rails
+# db:schema:load`. When creating a new database, `bin/rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(version: 0) do
+
+end
diff --git c/db/sharded_schema.rb w/db/sharded_schema.rb
new file mode 100644
index 0000000..3fd68a3
--- /dev/null
+++ w/db/sharded_schema.rb
@@ -0,0 +1,21 @@
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# This file is the source Rails uses to define your schema when running `bin/rails
+# db:schema:load`. When creating a new database, `bin/rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(version: 2021_02_10_182604) do
+
+  create_table "products", charset: "utf8", force: :cascade do |t|
+    t.string "name"
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+  end
+
+end
diff --git c/db/vitess/schema/sharded/vschema.json w/db/vitess/schema/sharded/vschema.json
new file mode 100644
index 0000000..00f12ba
--- /dev/null
+++ w/db/vitess/schema/sharded/vschema.json
@@ -0,0 +1,51 @@
+{
+  "sharded": true,
+  "vindexes": {
+    "use_shard_0": {
+      "type": "null"
+    },
+    "hash": {
+      "type": "hash"
+    }
+  },
+  "tables": {
+    "schema_migrations": {
+      "column_vindexes": [
+        {
+          "column": "version",
+          "name": "use_shard_0"
+        }
+      ],
+      "columns": [
+        {
+          "name": "version",
+          "type": "VARCHAR"
+        }
+      ]
+    },
+    "ar_internal_metadata": {
+      "column_vindexes": [
+        {
+          "column": "key",
+          "name": "use_shard_0"
+        }
+      ]
+    },
+    "products": {
+      "column_vindexes": [
+        {
+          "column": "id",
+          "name": "hash"
+        }
+      ]
+    },
+    "sharded_products": {
+      "column_vindexes": [
+        {
+          "column": "id",
+          "name": "hash"
+        }
+      ]
+    }
+  }
+}
diff --git c/docker-compose.yml w/docker-compose.yml
new file mode 100644
index 0000000..4e6274d
--- /dev/null
+++ w/docker-compose.yml
@@ -0,0 +1,26 @@
+version: "3.0"
+services:
+  vttest:
+    image: "vitess/vttestserver:mysql57"
+    command:
+      - "/vt/bin/vttestserver"
+      - "-alsologtostderr"
+      - "-port=2222"
+      - "-mysql_bind_host=0.0.0.0"
+      - "-num_shards=1,2"
+      - "-keyspaces=unsharded,sharded"
+      - "-schema_dir=/schema"
+    volumes:
+      - ./db/vitess/schema:/schema
+    ports:
+      # See below for how port numbers are calculated
+      # https://github.com/vitessio/vitess/blob/fbb4300bb37efcfc0c6468f586a5348ac0751c6f/go/vt/vttest/environment.go#L157
+      #
+      # grpc
+      - "2223:2223"
+      # vtcombo http
+      - "2222:2222"
+      # mysqld
+      - "2224:2224"
+      # vtcombo mysql (canonically vtgate)
+      - "2225:2225"
diff --git c/test/fixtures/products.yml w/test/fixtures/products.yml
new file mode 100644
index 0000000..7d41224
--- /dev/null
+++ w/test/fixtures/products.yml
@@ -0,0 +1,7 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  name: MyString
+
+two:
+  name: MyString
diff --git c/test/models/product_test.rb w/test/models/product_test.rb
new file mode 100644
index 0000000..3560151
--- /dev/null
+++ w/test/models/product_test.rb
@@ -0,0 +1,7 @@
+require "test_helper"
+
+class ProductTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end