created initial tables & models

app/models/like.rb

···
+require 'active_record'
+
+require_relative 'post'
+require_relative 'user'
+
+class Like < ActiveRecord::Base
+  validates_presence_of :time, :rkey
+  validates_length_of :rkey, maximum: 13
+
+  belongs_to :user, foreign_key: 'actor_id'
+  belongs_to :post
+end

app/models/post.rb

···
+require 'active_record'
+
+require_relative 'user'
+
+class Post < ActiveRecord::Base
+  validates_presence_of :time, :data, :rkey
+  validates :text, length: { minimum: 0, allow_nil: false }
+
+  validates_length_of :rkey, maximum: 13
+  validates_length_of :text, maximum: 1000
+  validates_length_of :data, maximum: 10000
+
+  belongs_to :user
+end

app/models/user.rb

···
+require 'active_record'
+
+require_relative 'like'
+require_relative 'post'
+
+class User < ActiveRecord::Base
+  validates_presence_of :did
+  validates_length_of :did, maximum: 260
+
+  has_many :posts
+  has_many :likes, foreign_key: 'actor_id'
+end

db/migrate/20250829000022_create_tables.rb

···
+class CreateTables < ActiveRecord::Migration[7.2]
+  def change
+    create_table :users, id: :integer do |t|
+      t.string "did", limit: 260, null: false
+    end
+
+    add_index :users, :did, unique: true
+
+    create_table :posts do |t|
+      t.integer "user_id", null: false
+      t.string "rkey", limit: 13, null: false
+      t.datetime "time", null: false
+      t.text "text", null: false
+      t.text "data", null: false
+    end
+
+    add_index :posts, [:user_id, :time, :id], order: { time: :desc, id: :desc }
+    add_index :posts, [:user_id, :rkey], unique: true
+
+    create_table :likes do |t|
+      t.integer "actor_id", null: false
+      t.string "rkey", limit: 13, null: false
+      t.datetime "time", null: false
+      t.bigint "post_id", null: false
+    end
+
+    add_index :likes, [:actor_id, :time, :id], order: { time: :desc, id: :desc }
+    add_index :likes, [:actor_id, :rkey], unique: true
+  end
+end

db/schema.rb

···
+# 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[7.2].define(version: 2025_08_29_000022) do
+  # These are extensions that must be enabled in order to support this database
+  enable_extension "plpgsql"
+
+  create_table "likes", force: :cascade do |t|
+    t.integer "actor_id", null: false
+    t.string "rkey", limit: 13, null: false
+    t.datetime "time", null: false
+    t.bigint "post_id", null: false
+    t.index ["actor_id", "rkey"], name: "index_likes_on_actor_id_and_rkey", unique: true
+    t.index ["actor_id", "time", "id"], name: "index_likes_on_actor_id_and_time_and_id", order: { time: :desc, id: :desc }
+  end
+
+  create_table "posts", force: :cascade do |t|
+    t.integer "user_id", null: false
+    t.string "rkey", limit: 13, null: false
+    t.datetime "time", null: false
+    t.text "text", null: false
+    t.text "data", null: false
+    t.index ["user_id", "rkey"], name: "index_posts_on_user_id_and_rkey", unique: true
+    t.index ["user_id", "time", "id"], name: "index_posts_on_user_id_and_time_and_id", order: { time: :desc, id: :desc }
+  end
+
+  create_table "users", id: :serial, force: :cascade do |t|
+    t.string "did", limit: 260, null: false
+    t.index ["did"], name: "index_users_on_did", unique: true
+  end
+end