Provide migration guide

CHANGELOG.md

@@ -4,6 +4,9 @@
 
 ## Master
 
+Due to the removal of legacy code, there are a few breaking changes in this new version that affect both template writers as well as developers. We've provided a migration guide to help you through these changes, which you can find here:
+[Migration Guide for 2.0](https://github.com/SwiftGen/StencilSwiftKit/blob/master/Documentation/MigrationGuide.md#stencilswiftkit-20-swiftgen-50)
+
 ### Bug Fixes
 
 * Fix `snakeToCamelCase` parameters information in README.  

Documentation/MigrationGuide.md

@@ -0,0 +1,21 @@
+## StencilSwiftKit 2.0 (SwiftGen 5.0) ##
+
+### For template writers:
+
+* We've removed our `join` array filter as Stencil provides it's own version that accepts a parameter. If you were using StencilSwiftKit's version, replace instances of:  
+```{{ myArray|join }}```  
+with:  
+```{{ myArray|join:", " }}```
+* We've refactored our `snakeToCamelCase` to accept arguments, thus removing the need for `snakeToCamelCaseNoPrefix`. If you were using the latter, replace instances of:  
+```{{ myValue|snakeToCamelCaseNoPrefix }}```  
+with:  
+```{{ myValue|snakeToCamelCase:true }}```
+
+### For developers using StencilSwiftKit as a dependency:
+
+We've removed the following deprecated `typealias`es:
+
+* `FilterError`: use `Filters.Error` instead.
+* `ParametersError`: use `Parameters.Error` instead.
+* `NumFilters`: use `Filters.Numbers` instead.
+* `StringFilters`: use `Filters.Strings` instead.