added controller tests for videos#show and videos#search
added controller tests for authentication
fixed one minor issue with the sessions controller spec
added video reviews, the TDD way :)
user can review a video
bug fixes and refactors follow Brandons comments
added feature to persist review content when no rating was given after submitting
fixed the issue with the last test, expect(asssigns(:review).content).to eq(...)
Merge pull request #3 from j1wu/week2

Week2