Fix fixtures in tasks_controller_tast to use task_participations fixtures, instead of no-longer existant tasks_users fixtures.  Now all functional tests pass!
Fix fixtures in tasks_controller_tast to use task_participations
fixtures, instead of no-longer existant tasks_users fixtures.  Now all
functional tests pass!

geoiq/digitalgazette,ajturner/crisiscommons,riseuplabs/crabgrass,nilclass/echosocial,adammck/crabgrass,adammck/crabgrass,adammck/crabgrass,nilclass/echosocial,riseuplabs/crabgrass,adammck/crabgrass,ajturner/crisiscommons,nilclass/echosocial,riseuplabs/crabgrass,nilclass/echosocial,riseuplabs/crabgrass,geoiq/digitalgazette,ajturner/crisiscommons,geoiq/digitalgazette,geoiq/digitalgazette,riseuplabs/crabgrass,ajturner/crisiscommons,riseuplabs/crabgrass,riseuplabs/crabgrass