Add packer_completion package

packages/packer_completion.rb

+require 'package'
+
+class Packer_completion < Package
+  description 'Add bash autocompletion for packer.'
+  homepage 'https://github.com/mrolli/packer-bash-completion'
+  version '1.0.0'
+  source_url 'https://github.com/mrolli/packer-bash-completion/archive/1.0.0.tar.gz'
+  source_sha256 '20ebfacd3f3a60f8dbd09e25b97d3b6e5049cbdf00a2d607fe79eaaef39e1eea'
+
+  binary_url ({
+  })
+  binary_sha256 ({
+  })
+
+  def self.install
+    system "install -Dm644 packer #{CREW_PREFIX}/share/packer-bash-completion/packer"
+  end
+
+  def self.postinstall
+    puts
+    puts "To complete installation, execute the following:".lightblue
+    puts "echo '# packer completion' >> ~/.bashrc".lightblue
+    puts "echo 'if [ -f #{CREW_PREFIX}/share/packer-bash-completion/packer ]; then' >> ~/.bashrc".lightblue
+    puts "echo '  source #{CREW_PREFIX}/share/packer-bash-completion/packer' >> ~/.bashrc".lightblue
+    puts "echo 'fi' >> ~/.bashrc".lightblue
+    puts "source ~/.bashrc".lightblue
+    puts
+  end
+end