== Version 0.8.0
This release makes the jump from using Gecode 1.3.1 to using Gecode 2.1.1 . 
The following changes have been made to the interface as a result of the jump.

* The distinct constraint for sets has been removed.
* Added the propagation kind option to the non-set constraints.

== Version 0.7.1
This release adds boolean linear constraints.

* Set domain constraints now checks illegal parameters when it's added (rather than when the search begins).
* Added boolean linear constraint.

== Version 0.7.0
This release adds the set selection and operation constraints.

* Added set selection constraints (set array access, select union, select intersection (optionally with specified universe) and select disjoint).
* Added set operation constraints (union, minus, disjoint_union and intersection) on pairs of set variables or set constants with variable or constant right hand side.
* Added set operation constraints on enumerations of sets.

== Version 0.6.1
This release fixes various bugs introduced in 0.6.0 and changes the way that
int variable domains are specified (breaking backward-compatibility).

* The domain for int variables can no longer be specified as several individual elements, it has to be specified as either a single element, a range or another enumeration.
* Fixed a bug with set cardinality, min and max constraints using composite sugar.
* Variables can now be created inside the optimization block.

== Version 0.6.0
This release adds most of the remaining set constraints. It also makes 
backward-compatibility breaking changes to the way that properties of variables
are accessed.

* Added channel constraints involving set variables.
* Added set min and max constraints.
* Added set sum constraints (optionally weighted or substituted).
* Added include (match) constraint for sets.
* Added distinct constraints (distinct and at most one) for sets.
* Added branch and bound search (optimization search). It's quite shaky at the moment though.
* Assigned values of variables are now always accessed using #value instead of the various previous methods. The methods for extracting information from set variables have been changed and renamed.
* Enumerations containing variables now provide a convenience method #values which returns an array of the enum's values.

== Version 0.5.0
This release adds set variables and some of their constraints, along with the 
last of the boolean constraints.

* Added exclusive or and implication.
* Added conjunction and disjunction for boolean enumerations.
* Added set variables. They are created using Model{#set_var, #set_var_array, #set_var_matrix}.
* Added domain constraints for set variables.
* Added relation constraints for set variables.
* Added set cardinality constraints.

== Version 0.4.0
This release adds most of the integer variable constraints supported by Gecode.

* [#11861] Fixed a bug stopping the creation of int variables with non-range domains.
* Added domain constraints for int variables.
* Added equality constraint for int enums.
* Matrices of integer and boolean variables can now be created using Model#int_var_matrix Model#bool_var_matrix.
* Added channel constraint for int enums.
* Added element constraints (variable array access).
* Added count constraints.
* Added sortedness constraints.
* Added arithmetic constraints (min, max, abs and variable multiplication).

== Version 0.3.0
This release fleshes out the existing constraints with things such as 
reification and adds boolean variables and their basic constraints.

* The constructor of Gecode::Model no longer has to be called by classes inheriting from it.
* Added Model#reset! which resets a model after search.
* Added Model#solution which passes the first solution to a block and returns the result of that block.
* Added Model#each_solution which iterates over each solution.
* Added boolean variables. They are created using Model#bool_var and Model#bool_var_array .
* Added two options to constraints: propagation strength and reification variable.
* Linear and simple relation constraints can now also be specified using #equal, #equal_to, #greater, #greater_than,... in addition to comparison operators.
* Added distinct with offsets.
* Simple relation constraints can now be used to specify relations between two variables.
* Added basic boolean domain constraints along with conjunction and disjunction.
* Added syntactic sugar for combining reifiable constraints with | and &.

== Version 0.2.0
This is the first release of Gecode/R, a Ruby interface to Gecode.

* Added support for finite domain integers.
* Added some basic relation, linear and distinct constraints.
* Added the basis needed to model problems and find the first solution.