move not_selected from external tools settings to it's own column

fixes: PLAT-646

Test Plan:
 * Install an external tool with the property "not_selectable" as true
 * when you look in the asmnt/module item external tool list the tool
   should not be listed

Change-Id: If66e09b83373fad83274d0120cb464e7caf60c83
Reviewed-on: https://gerrit.instructure.com/41205
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Reviewed-by: Bracken Mosbacker <bracken@instructure.com>
Product-Review: Bracken Mosbacker <bracken@instructure.com>

app/models/context_external_tool.rb

@@ -267,12 +267,12 @@ class ContextExternalTool < ActiveRecord::Base
     settings[:text]
   end
 
-  def not_selectable=(bool)
-    settings[:not_selectable] = Canvas::Plugin.value_to_boolean(bool)
+  def not_selectable
+    !!read_attribute(:not_selectable)
   end
 
-  def not_selectable
-    settings[:not_selectable]
+  def not_selectable=(bool)
+    write_attribute(:not_selectable, Canvas::Plugin.value_to_boolean(bool))
   end
 
   def selectable

app/models/importers/context_external_tool_importer.rb

@@ -40,6 +40,7 @@ module Importers
       end
       item.domain = hash[:domain] unless hash[:domain].blank?
       item.privacy_level = hash[:privacy_level] || 'name_only'
+      item.not_selectable = hash[:not_selectable] if hash[:not_selectable]
       item.consumer_key ||= hash[:consumer_key] || 'fake'
       item.shared_secret ||= hash[:shared_secret] || 'fake'
       item.settings = create_tool_settings(hash)

db/migrate/20140916195352_add_external_tools_not_selectable_column.rb

@@ -0,0 +1,7 @@
+class AddExternalToolsNotSelectableColumn < ActiveRecord::Migration
+  tag :predeploy
+
+  def change
+    add_column :context_external_tools, :not_selectable, :boolean
+  end
+end

lib/cc/importer/blti_converter.rb

@@ -80,6 +80,7 @@ module CC::Importer
         
         if ext[:platform] == CANVAS_PLATFORM
           tool[:privacy_level] = ext[:custom_fields].delete 'privacy_level'
+          tool[:not_selectable] = ext[:custom_fields].delete 'not_selectable'
           tool[:domain] = ext[:custom_fields].delete 'domain'
           tool[:consumer_key] = ext[:custom_fields].delete 'consumer_key'
           tool[:shared_secret] = ext[:custom_fields].delete 'shared_secret'

spec/controllers/external_tools_controller_spec.rb

@@ -417,7 +417,7 @@ describe ExternalToolsController do
       assigns[:tool].url.should == "http://example.com/other_url"
       assigns[:tool].consumer_key.should == "key"
       assigns[:tool].shared_secret.should == "secret"
-      assigns[:tool].not_selectable.should == "true"
+      assigns[:tool].not_selectable.should be_truthy
       assigns[:tool].has_placement?(:editor_button).should be_true
     end