Add reducer tests

[StevenTCramer]

Move Jest to dev dependency. Updated to latest and updated snapshots.

Added redux-mock-store as dev dependency.

Added tests for Docs.

[RyanCCollins]

Hey @StevenTCramer I am getting a bunch of errors after merging with master when running the deploy script that seem to be related to your recent config changes. In the future, we need to try to automate the testing of the deployment and server-rendering to make sure changes like this aren't breaking. We should also probably keep configuration changes on separate PRs when possible.

Would you mind running the deploy and server to ensure that this is resolved before we merge into Master?

ERROR in /Users/myMac/Developer/works-in-progress/open-source-maintaining/scalable-react-ts-boilerplate/src/client/types.ts
(2,31): error TS2307: Cannot find module 'containers/TodoApp/types'.
ERROR in /Users/myMac/Developer/works-in-progress/open-source-maintaining/scalable-react-ts-boilerplate/src/client/types.ts
(3,28): error TS2307: Cannot find module 'containers/Docs/types'.
ERROR in ./src/client/state.ts
(2,52): error TS2307: Cannot find module 'containers/App/reducers'.
ERROR in ./src/client/state.ts
(3,63): error TS2307: Cannot find module 'containers/Docs/state'.
ERROR in ./src/client/state.ts
(4,69): error TS2307: Cannot find module 'containers/TodoApp/state'.
ERROR in ./src/client/reducers.ts
(5,24): error TS2307: Cannot find module 'containers/App/reducers'.
ERROR in ./src/client/reducers.ts
(6,25): error TS2307: Cannot find module 'containers/Docs/reducers'.
ERROR in ./src/client/reducers.ts
(7,28): error TS2307: Cannot find module 'containers/TodoApp/reducer'.
ERROR in ./src/client/containers/Home/presentation.tsx
(3,28): error TS2307: Cannot find module 'components/Button'

Thank you!

[RyanCCollins]

Let's continue this on #50, as it includes the merged in master that is failing the deployment script.