Add db_workspace command & other db refactoring.

* Added "workspaces" table and associated ActiveRecord class.
 * Moved ActiveRecord models from db_objects.rb into separate files.
 * Do the DB migration check every time you connect (was previously done
   during db_create).
 * Use :dependent => :destroy associations so that we don't have to
   manually delete the dependent objects.

git-svn-id: file:///home/svn/framework3/trunk@7861 4d416f70-5f16-0410-b530-b9f4589650da

data/sql/migrate/002_add_workspaces.rb

@@ -0,0 +1,29 @@
+class AddWorkspaces < ActiveRecord::Migration
+
+	def self.up
+		create_table :workspaces do |t|
+			t.string    :name
+			t.timestamps
+		end
+
+		change_table :hosts do |t|
+			t.integer   :workspace_id, :required => true
+		end
+
+		remove_index :hosts, :column => :address
+
+		w = Msf::DBManager::Workspace.default
+		Msf::DBManager::Host.update_all ["workspace_id = ?", w.id]
+	end
+
+	def self.down
+		drop_table :workspaces
+
+		change_table :hosts do |t|
+			t.remove   :workspace_id
+		end
+
+		add_index :hosts, :address, :unique => true
+	end
+
+end