Add gemfile as an install option
user
```ruby
Gem::Specification.new do |s|
  s.name              = 'schema-evolution-manager'
  s.version           = '0.0.0'
  s.date              = Time.now.strftime('%Y-%m-%d')
  s.summary           = "Schema Evolution Manager makes it very simple for engineers to contribute schema changes to a postgresql database, managing the schema evolutions as proper source code."
  s.authors           = ["Michael Bryzek"]
  s.files             = %w( README.md )
  s.files             += Dir.glob("bin/**/*")
  s.files             += Dir.glob("lib/**/*")
  s.files             += Dir.glob("template/**/*")
  s.executables       = ["sem-add", "sem-apply", "sem-config", "sem-dist", "sem-info", "sem-init"]
end
```
assistant