Added migrate file to take out the 0 values in the author_feedback_review_id of Assignments table and replace them with nulls.
Added migrate file to take out the 0 values in the author_feedback_review_id of Assignments table and replace them with nulls.

git-svn-id: f67d969b640da65cb7bc1d229e09fd6d2db44ae1@418 392d7b7b-3f31-0410-9dc3-c95a9635ea79

akshayjain114/expertiza,redsock88/expertiza,ApertureScienceInnovators/expertiza,mhhassan/expertiza,KunmiaoYang/expertiza,sid5788/expertiza,ApertureScienceInnovators/expertiza,urmilparikh95/expertiza,michaelamoran/expertiza,kira0992/expertiza,rmmaily/expertiza,akshayjain114/expertiza,sid5788/expertiza,rmmaily/expertiza,expertiza/expertiza,akshayjain114/expertiza,redsock88/expertiza,KunmiaoYang/expertiza,akshayjain114/expertiza,sid5788/expertiza,sid5788/expertiza,michaelamoran/expertiza,redsock88/expertiza,kira0992/expertiza,joshio1/expertiza,kira0992/expertiza,rmmaily/expertiza,urmilparikh95/expertiza,joshio1/expertiza,ApertureScienceInnovators/expertiza,michaelamoran/expertiza,arpitashekhar/expertiza,KunmiaoYang/expertiza,KunmiaoYang/expertiza,arpitashekhar/expertiza,mhhassan/expertiza,kira0992/expertiza,ApertureScienceInnovators/expertiza,expertiza/expertiza,mhhassan/expertiza,mhhassan/expertiza,rmmaily/expertiza,expertiza/expertiza,urmilparikh95/expertiza,redsock88/expertiza,michaelamoran/expertiza,arpitashekhar/expertiza,joshio1/expertiza,urmilparikh95/expertiza,joshio1/expertiza,expertiza/expertiza,arpitashekhar/expertiza