cs2109 - challenge admin

i faced assets:precompile issue, and somehow fixed it...

i had to include some JS and CSS files manually as they are not compiled automatically. please refer to _application.html.erb_ line 21-24 and 34-40

`
    <link href="/assets/select2.css" rel="stylesheet">
    <link href="/assets/datepicker/base.css" rel="stylesheet">
    <link href="/assets/datepicker/clean.css" rel="stylesheet">
    <link href="/assets/jquery.plupload.queue.css" rel="stylesheet">
`

`
    <%= javascript_include_tag "select2" %>
    <%= javascript_include_tag "datepicker" %>
    <%= javascript_include_tag "plupload" %>
    <%= javascript_include_tag "plupload.html4" %>
    <%= javascript_include_tag "plupload.html5" %>
    <%= javascript_include_tag "jquery.plupload.queue" %>
    <%= javascript_include_tag "ckeditor-jquery" %>
`

all fields except "community judging" and "private community" are implemented as required in the challenge