Tag release v1.0.0.pre.7

References: #14, #17

* Upgrading - Aws::Record - This release includes changes to validation and
  to the `#save` and `#save!` methods. With this release, the validation hooks
  in `Aws::Record::Attribute` have been removed. Additionally, `#save` will
  resume raising exceptions on client errors. However, `#save` and `#save!`
  will attempt to call `#valid?` if defined on the model, and will return false
  or raise as appropriate if that method is defined and returns false.

  As a part of this change, we've removed the built in `#valid?` and `#errors`
  methods. If you were a user of those, consider bringing your own validation
  library such as `ActiveModel::Validations`.

* Issue - Aws::Record - Removes `#valid?` and `#errors` methods, which caused a
  conflict with the ability to bring your own validation library such as
  `ActiveModel::Validations`. Added tests as an example and to test
  compatibility.

Tag release v1.0.0.pre.6

* Feature - Aws::Record::Attributes - Improves default marshaling behavior for
  set types. Now, if your object responds to `:to_set`, such as an Array, it
  will automatically be marshaled to a set type when persisted.

Tag release v1.0.0.pre.5

References: #1, #11, #13, #2, #7

* Upgrading - Aws::Record - The conditional put/update logic added to `#save`
  and `#save!` is not backwards compatible in some cases. For example, the
  following code would work in previous versions, but not in this version:

  ```ruby
  item = Model.new # Assume :id is the hash key, there is no range key.
  item.id = 1
  item.content = "First write."
  item.save

  smash = Model.new
  smash.id = 1
  smash.content = "Second write."
  smash.save # false, and populates the errors array.
  smash.save(force: true) # This will skip the conditional check and work.

  updatable = Model.find(id: 1)
  updatable.content = "Update write."
  updatable.save # This works and uses an update client call.
  ```

  If you want to maintain previous behavior of unconditional puts, add the
  `force: true` option to your `#save` calls. However, this risks overwriting
  unmodeled attributes, or attributes excluded from your projection. But, the
  option is available for you to use.

* Upgrading - Aws::Record - The split of the `#save` method into `#save` and
  `#save!` breaks when your code is expecting `#save` to raise exceptions.
  `#save` will return false on a failed write and populate an `errors` array.
  If you wish to raise exceptions on failed save attempts, use the `#save!`
  method.

* Feature - Aws::Record - Adds logic to determine if `#save` and `#save!` calls
  should use `Aws::DynamoDB::Client#put_item` or
  `Aws::DynamoDB::Client#update_item`, depending on which item attributes are
  marked as dirty. `#put_item` calls are also made conditional on the key not
  existing, so accidental overwrites can be prevented. Old behavior of
  unconditional `#put_item` calls can be done using the `force: true` parameter.

* Feature - Aws::Record - Separates the `#save` method into `#save` and
  `#save!`. `#save!` will raise any errors that occur during persistence, while
  `#save` will populate an errors array and cause `#valid?` calls on the item to
  return `false`.

* Issue - Aws::Record - Changed how default table names are generated. In the
  past, the default table name could not handle class names that included
  modules. Now, module namespaces are appended to the default table name. This
  should not affect any existing model classes, as previously any affected
  models would have failed to create a table in DynamoDB.

Tag release v1.0.0.pre.4

References: #5

* Feature - Aws::Record::DirtyTracking - `Aws::Record` items will now keep track
  of "dirty" changes from database state. The DirtyTracking module provides a
  set of helper methods to handle dirty attributes.

Tag release v1.0.0.pre.3

References: #4

Tag release v1.0.0.pre.2

References: #3

* Feature - Aws::Record - Provides a low-level interface for the client `#query`
  and `#scan` methods. Query and Scan results are surfaces as an enumerable
  collection of `Aws::Record` items.

* Feature - Aws::Record - Support for adding global secondary indexes and local
  secondary indexes to your model classes. Built-in support for creating these
  indexes at table creation time.

Tag release v1.0.0.pre.1

* Feature - Aws::Record - Initial development release of the `aws-record` gem.