Made some progress

app/models/account.rb

@@ -1,6 +1,38 @@
 class Account < ActiveRecord::Base
+  # Local users
+  has_one :user, inverse_of: :account
+
+  # Timelines
+  has_many :stream_entries, inverse_of: :account
   has_many :statuses, inverse_of: :account
 
+  # Follow relations
+  has_many :active_relationships,  class_name: 'Follow', foreign_key: 'account_id',        dependent: :destroy
+  has_many :passive_relationships, class_name: 'Follow', foreign_key: 'target_account_id', dependent: :destroy
+
+  has_many :following, through: :active_relationships,  source: :target_account
+  has_many :followers, through: :passive_relationships, source: :account
+
+  def follow!(other_account)
+    self.active_relationships.create!(target_account: other_account)
+  end
+
+  def unfollow!(other_account)
+    self.active_relationships.find_by(target_account: other_account).destroy
+  end
+
+  def following?(other_account)
+    following.include?(other_account)
+  end
+
+  def local?
+    self.domain.nil?
+  end
+
+  def keypair
+    self.private_key.nil? ? OpenSSL::PKey::RSA.new(self.public_key) : OpenSSL::PKey::RSA.new(self.private_key)
+  end
+
   def subscription(webhook_url)
     @subscription ||= OStatus2::Subscription.new(self.remote_url, secret: self.secret, token: self.verify_token, webhook: webhook_url, hub: self.hub_url)
   end