Allow nulls in migration name column
Allow nulls in migration name column

This is because existing users of Phinx will not have values for this column, and so it should correctly specify that it is expecting to have null values.
aCodify/phinx,rquadling/phinx,daniel-gomes-sociomantic/phinx,Thamrongsak/phinx,aCodify/phinx,ikagawa/phinx,dankempster/phinx,robmorgan/phinx