Pull Request: C5_Mohab_468_Contest_Standings_5.25

<h3>For Scenario Reviewers:</h3>
<ul>
<li><h4>Navigate to contests/1/standings, a table containing students versus problems should be visible</h4></li>
<li><h4>The green color indicates that a problem was solved correctly and the red color indicates the opposite.</h4></li>
<li><h4>The numbers inside the green box indicates :  (Number of trials until first correct submission ) / (Time in minutes between the first correct submission and contest start time )</h4>
<p> To Test: </p>
Change one of the submissions to be right answer 
<ul>
<li>c = ContestProgress.find(4)</li>
<li>c.status = true</li>
<li>c.save</li>
<li> Notice the changed value in the time part </li>
</ul>
</li>
<li><h4> Students are ranked by the number of correct problems they solved, but if two or more students have the same number of correct submission, the one with earlier submission gets higher rank.</h4>
<p> To Test: </p>
Currently studentI and studentIII solved equal number of problems, change the submission date for studentI one so that studentIII will have advantage in submission time
<ul>
<li>c = ContestProgress.find(1)</li>
<li>c.updated_at = Time.now</li>
<li>c.save</li>
<li>Notice the change in ranks</li>
</ul> 
</li>
<li><h4>If the contest has finished the student will be informed</h4>
<p>To Test:</p>
<ul>
<li>c = Contest.find(1)</li>
<li>c.end_time = Time.new(2014, 5, 2)</li>
<li>c.save</li>
</ul>
</li>
 
<hr>
@MussabElDash @linsara @nadineadel @Husseny