added channels into nested attributes
insert channel_ids into permitted params
Admin can mark a check box with the channels that the project belongs [13809905]
Merge branch 'master' into feature/add_channels_into_project_edit-13809905

* master:
  remove mixpanel from this partial
  whitespace into channel/posts title
  use analytics helpers instead direct render
  create a analytics helpers to handler with methods that render the analytics scripts
  only admin users can set the GA Code into channel profile/edit
  added column to save the google analytics tracking code into channel
Merge pull request #801 from devton/feature/add_channels_into_project_edit-13809905

Feature/add channels into project edit 13809905