Ava DuVernay, the filmmaker behind films for TV and theaters including "When They See Us," "Colin in Black & White" and "Queen Sugar," has released a free, online resource that includes lesson plans or "learning companions" that teachers can use to accompany instruction about her films. The resources include tools to examine voting rights after students watch "Selma," which centers on three months in Martin Luther King Jr.'s life and the harrowing 1965 march from Selma, Ala., to Montgomery, capital of the state.