Add GPG support for reading router.db

Gemfile

@@ -1,3 +1,3 @@
 source 'https://rubygems.org'
-
+gem 'gpgme'
 gemspec

README.md

@@ -235,12 +235,15 @@ oxidized
 
 Now tell Oxidized where it finds a list of network devices to backup configuration from. You can either use CSV or SQLite as source. To create a CSV source add the following snippet:
 
+Note: If gpg is set to anything other than false it will attempt to decrypt the file contents
 ```
 source:
   default: csv
   csv:
     file: ~/.config/oxidized/router.db
     delimiter: !ruby/regexp /:/
+    gpg: 'false'
+    gpg_password: 'password'
     map:
       name: 0
       model: 1

lib/oxidized/manager.rb

@@ -3,6 +3,7 @@ module Oxidized
   require 'oxidized/input/input'
   require 'oxidized/output/output'
   require 'oxidized/source/source'
+  require 'gpgme'
   class Manager
     class << self
       def load dir, file

lib/oxidized/source/csv.rb

@@ -11,14 +11,21 @@ def setup
       Oxidized.asetus.user.source.csv.delimiter = /:/
       Oxidized.asetus.user.source.csv.map.name  = 0
       Oxidized.asetus.user.source.csv.map.model = 1
+      Oxidized.asetus.user.source.csv.gpg       = false
       Oxidized.asetus.save :user
       raise NoConfig, 'no source csv config, edit ~/.config/oxidized/config'
     end
   end
 
   def load
     nodes = []
-    open(File.expand_path @cfg.file).each_line do |line|
+    if @cfg.gpg != 'false'
+      crypto = GPGME::Crypto.new :password => @cfg.gpg_password
+      file   = crypto.decrypt(File.open(@cfg.file)).to_s
+    else
+      file = open(File.expand_path @cfg.file)
+    end
+    file.each_line do |line|
       next if line.match(/^\s*#/)
       data  = line.chomp.split(@cfg.delimiter, -1)
       next if data.empty?