admin.cr

class Admin < BaseModel
  table do
    column name : String
    belongs_to user : User
  end
end

crash output

Compiling...
Done compiling
Invalid memory access (signal 11) at address 0x0
[0x5576e3726776] *CallStack::print_backtrace:Int32 +118
[0x5576e36eb559] __crystal_sigfault_handler +217
[0x7fc6754de890] ???
[0x5576e36d6624] __crystal_main +14212
[0x5576e3a4c476] *Crystal::main_user_code<Int32, Pointer(Pointer(UInt8))>:Nil +6
[0x5576e3a4c3d9] *Crystal::main<Int32, Pointer(Pointer(UInt8))>:Int32 +41
[0x5576e36e2836] main +6
[0x7fc674887b97] __libc_start_main +231
[0x5576e36d2dba] _start +42
[0x0] ???

create.cr

class Admins::Create < BrowserAction
  route do
    SignUpUser.create(params) do |operation, admin|
      if admin
        flash.success = "The record has been saved"
        redirect Show.with(admin.id)
      else
        flash.failure = "It looks like the form is not valid"
        html NewPage, operation: operation
      end
    end
  end
end

new.cr

class Admins::New < BrowserAction
  route do
    html NewPage, operation: SignUpUser.new
  end
end

new_page.cr

class Admins::NewPage < MainLayout
  needs operation : SignUpUser
  quick_def page_title, "New"

  def content
    h1 "New"
    render_admin_form(@operation)
  end

  def render_admin_form(op)
    form_for Admins::Create do
      mount Shared::Field.new(op.save_admin_op.name), &.text_input(autofocus: "true")
      

      mount Shared::Field.new(op.email), &.email_input(autofocus: "true")
      mount Shared::Field.new(op.password), &.password_input
      mount Shared::Field.new(op.password_confirmation), &.password_input

      submit "Save", data_disable_with: "Saving..."
    end
  end
end

sign_up_user.cr

class SignUpUser < User::SaveOperation
  param_key :user
  # Change password validations in src/operations/mixins/password_validations.cr
  include PasswordValidations
  
  @_save_admin_op : SaveAdmin?
  
  def save_admin_op
    @_save_admin_op ||= SaveAdmin.new(params)
  end

  permit_columns email
  attribute password : String
  attribute password_confirmation : String

  before_save do
    validate_uniqueness_of email
    Authentic.copy_and_encrypt password, to: encrypted_password
  end

  after_save create_admin

  private def create_admin(user : User)
    save_admin_op.user_id.value = user.id
    if !save_admin_op.save
      database.rollback
    end
  end

end