bin/rails db:migrateコマンドを入力するとターミナルで以下のようなエラー文が。

Creating staff_members....
rails aborted!
ActiveModel::UnknownAttributeError: unknown attribute 'password' for StaffMember.

StaffMemberのpasswordが存在しないよと仰ってます。
最初にmigrationファイルを疑ってかかるも、passwordに関する記述は間違っていませんでした。続いてモデルを見に行くことに。

staff_member.rb

class StaffMember < ApplicationRecord
  include EmailHolder
  include PersonalNameHolder
  has_many :events, class_name:"StaffEvent", dependent: :destroy

  
  
  validates :start_date ,presence: true , date:{
    after_or_equal_to: Date.new(2000,1,1),
    before: -> (obj) { 1.year.from_now.to_date },
    allow_blank: true
  }
  validates :end_date, date: {
    after: :start_date,
    before: -> (obj) { 1.year.from_now.to_date },
    allow_blank: true
  }
  
  def active?
    !suspended && start_date <= Date.today &&
      (end_date.nil? || end_date > Date.today)
  end
end

PasswordHolderというmoduleを継承していないことが判明しました。

staff_member.rb

class StaffMember < ApplicationRecord
  include EmailHolder
  include PersonalNameHolder
  include PasswordHolder            <=ここを追記
  has_many :events, class_name:"StaffEvent", dependent: :destroy

  
  
  validates :start_date ,presence: true , date:{
    after_or_equal_to: Date.new(2000,1,1),
    before: -> (obj) { 1.year.from_now.to_date },
    allow_blank: true
  }
  validates :end_date, date: {
    after: :start_date,
    before: -> (obj) { 1.year.from_now.to_date },
    allow_blank: true
  }
  
  def active?
    !suspended && start_date <= Date.today &&
      (end_date.nil? || end_date > Date.today)
  end
end

エラーが解消しました。

bash-4.4$ bin/rails db:reset
Dropped database 'baukis2_development'
Dropped database 'baukis2_test'
Created database 'baukis2_development'
Created database 'baukis2_test'
Creating staff_members....
Creating administrators....
Creating staff_events....
Creating customers....
bash-4.4$