class CreateMentions

# File lib/generators/mention_system/templates/migration.rb, line 10
def change
  ###
  # Mentions table creation
  ###
  create_table :mentions do |t|
    ###
    # Mentionee id field and mentionee type field definition
    ###
    t.references :mentionee, polymorphic: true

    ###
    # Mentioner id fiel and mentioner type field definition
    ###
    t.references :mentioner, polymorphic: true

    ###
    # Timestamps fields definition
    ###
    t.timestamps null: false
  end

  ###
  # Mentions table mentionee id field and mentionee type field index addition
  ###
  add_index :mentions, [:mentionee_id, :mentionee_type], name: "mentions_mentionee_idx"

  ###
  # Mentions table mentioner id field and mentioner type field index addition
  ###
  add_index :mentions, [:mentioner_id, :mentioner_type], name: "mentions_mentioner_idx"

  ###
  # Mentions table mentionee id field and mentionee type field and mentioner id field and mentioner type field unique index addition
  ###
  add_index :mentions, [:mentionee_id, :mentionee_type, :mentioner_id, :mentioner_type], name: "mentions_mentionee_mentioner_idx", unique: true
end