minor #552 change to bin/console (diaboloshogunate)
minor #552 change to bin/console (diaboloshogunate)

This PR was squashed before being merged into the 3.1.x-dev branch (closes #552).

Discussion
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change to bin/console

symfony 3 uses `bin/console` instead of `app/console`. It is stated in the caution box but since this doc is for symfony 3.x we should show the `bin/console` in the examples instead of the old way.

Commits
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be39c03 change to bin/console

sensiolabs/SensioGeneratorBundle,sensiolabs/SensioGeneratorBundle