Option to persist mails in sqlite database at path

.gitignore

@@ -2,3 +2,4 @@ rdoc
 *.gem
 
 .sass-cache
+*.sqlite

lib/mail_catcher.rb

@@ -108,6 +108,10 @@ def parse! arguments=ARGV, defaults=@defaults
           end
         end
 
+        parser.on('-p', '--persist [PATH]', 'Persist messages in database at path (messages.sqlite by default)') do |path|
+          options[:persist] = path || 'messages.sqlite'
+        end
+
         parser.on('-v', '--verbose', 'Be more verbose') do
           options[:verbose] = true
         end
@@ -130,6 +134,8 @@ def run! options=nil
 
     Thin::Logging.silent = true
 
+    MailCatcher::Mail.db_path = options[:persist]
+
     # One EventMachine loop...
     EventMachine.run do
       # Get our lion on if asked

lib/mail_catcher/mail.rb

@@ -4,11 +4,13 @@
 require 'eventmachine'
 
 module MailCatcher::Mail extend self
+  attr_accessor :db_path
+
   def db
     @__db ||= begin
-      SQLite3::Database.new(':memory:', :type_translation => true).tap do |db|
+      SQLite3::Database.new(db_path || ':memory:', :type_translation => true).tap do |db|
         db.execute(<<-SQL)
-          CREATE TABLE message (
+          CREATE TABLE IF NOT EXISTS message (
             id INTEGER PRIMARY KEY ASC,
             sender TEXT,
             recipients TEXT,
@@ -20,7 +22,7 @@ def db
           )
         SQL
         db.execute(<<-SQL)
-          CREATE TABLE message_part (
+          CREATE TABLE IF NOT EXISTS message_part (
             id INTEGER PRIMARY KEY ASC,
             message_id INTEGER NOT NULL,
             cid TEXT,