Source does not contain any versions of 'sendpulse-rest-api-ruby'

```
#Gemfile
gem 'sendpulse-rest-api-ruby', :github => 'sendpulse/sendpulse-rest-api-ruby'
```

```
bundle install
```
```
Could not find gem 'sendpulse-rest-api-ruby' in git://github.com/sendpulse/sendpulse-rest-api-ruby.git (at master@4387cb3).
Source does not contain any versions of 'sendpulse-rest-api-ruby'

```