Working implementation for issue-1216
issue 1216: added functional test file
Revert "issue 1216: added functional test file"

This reverts commit 6b69db132c6b50aa3885c7556044694668eb75de.
isue-1216: added functional tests
Revert "isue-1216: added functional tests"

This reverts commit ac1f4420d05eb2927117bb9332a4c29da34d6201.
issue-1216: added functional tests
issue-1216: improved code quality
When there is no marks self.total_mark is 0. Condition is used to avoid division by 0.
Fix issue #1388
New test: if an assigment has no marks and was completed and released to student should has values median and average results values equal to 0. 

Equation that divides by total marks (0 if no marks in the assingment) should not be reached.
Correcting lines that are setup and verification.
Correcting comment.
Verify if students_counts is not zero, avoiding division by zero
Fix: schema.rb
Merge branch 'issue-1333'
Merge branch 'master' of github.com:MarkUsProject/Markus
Merge branch 'master' of github.com:MarkUsProject/Markus
Fix to issue #1402
Merge branch 'master' of github.com:MarkUsProject/Markus
prevent enter from releasing grades
Merge pull request #1410 from Gerb11/master

Closes #1402: UI Alignment error when sorting