```ruby
require 'spec_helper'

describe Citygram::Models::Publisher do
  it 'has many subscriptions' do
    type = Publisher.association_reflections[:subscriptions][:type]
    expect(type).to eq :one_to_many
  end

  it 'has many events' do
    type = Publisher.association_reflections[:events][:type]
    expect(type).to eq :one_to_many
  end

  it 'whitelists mass-assignable columns' do
    expect(Publisher.allowed_columns.sort).to eq [:title, :endpoint, :city, :active, :icon].sort
  end

  it 'requires a title' do
    publisher = build(:publisher, title: '')
    expect(publisher).not_to be_valid
  end

  it 'requires a fully qualified endpoint' do
    publisher = build(:publisher, endpoint: 'foo.com/events')
    expect(publisher).not_to be_valid
  end

  it 'requires a unique title' do
    publisher = create(:publisher)
    other = build(:publisher, title: publisher.title)
    expect(other).not_to be_valid
  end

  it 'requires a unique endpoint' do
    publisher = create(:publisher)
    other = build(:publisher, endpoint: publisher.endpoint)
    expect(other).not_to be_valid
  end
end
```

Add spec for publisher validation
user
```ruby
require 'spec_helper'

describe Citygram::Models::Publisher do
  it 'has many subscriptions' do
    type = Publisher.association_reflections[:subscriptions][:type]
    expect(type).to eq :one_to_many
  end

  it 'has many events' do
    type = Publisher.association_reflections[:events][:type]
    expect(type).to eq :one_to_many
  end

  it 'whitelists mass-assignable columns' do
    expect(Publisher.allowed_columns.sort).to eq [:title, :endpoint, :city, :active, :icon].sort
  end

  it 'requires a title' do
    publisher = build(:publisher, title: '')
    expect(publisher).not_to be_valid
  end

  it 'requires a fully qualified endpoint' do
    publisher = build(:publisher, endpoint: 'foo.com/events')
    expect(publisher).not_to be_valid
  end

  it 'requires a unique title' do
    publisher = create(:publisher)
    other = build(:publisher, title: publisher.title)
    expect(other).not_to be_valid
  end

  it 'requires a unique endpoint' do
    publisher = create(:publisher)
    other = build(:publisher, endpoint: publisher.endpoint)
    expect(other).not_to be_valid
  end

  it 'requires a city' do
    publisher = build(:publisher, city: '')
    expect(publisher).not_to be_valid
  end
end
```
assistant