Fix lock and pin message

The unlock/unpin message was in place of the lock/pin message.
Merge pull request #400 from fracek/fix_pin_lock_italian

Fix lock and pin message in italian transaltion
Partially completed Japanese localizations
Add localeapp to forem
Add Contributing guidelines
Add Gemfile(.lock) requirements to CONTRIBUTING.md
Merge pull request #407 from BanzaiMan/japanese_l18n

Partially completed Japanese localizations
Add Japanese in translation list