removed unnecessary semicolon.
added fkey on column competency_id to objective table. refs #3237
created migration for adding a fkey on column competency_id to objective table. refs #3237
bumped migration version number. refs #3237
updated objective DAO to save competency_id with a NULL value if a falsy value is provided. refs #3237
changed "unassigned" competency id value for objectives from -1 to 0. refs #3237
Merge pull request #142 from ucsflibtopfstedt/feat3237

added foreign key constraint on "competency_id" column in "objective" table