v4.0.0-alpha.1

Breaking

• Fixes incompatibility with Ember Data Model Fragments 5.0.0-beta+ and Ember Data 3.13+ #449 @patocallaghan
• Remove deprecated helpers #463 @patocallaghan
• Replace polyfill assign with Object.assign #481 @drouhard

Internal

• Upgrade to Ember 3.24 #443 @patocallaghan
• Upgrade to Ember 3.28 #448 @patocallaghan
• Fix a bunch of deprecations #461 @patocallaghan
• Fix this-property-fallback deprecations #462 @patocallaghan
• Add release-it to repo and generate initial CHANGELOG.md #454 @patocallaghan
• refactor: octane dummy app files #474 @Techn1x
• chore: update active-model-adapter to 3.0.1 #476 @Techn1x