Improve URL Value Converters documentation

Author: devxoul

README.md

@@ -216,35 +216,34 @@ Navigator.open("myapp://alert?title=Hi", context: context)
 ```
 
 
-#### Setting custom validators for placeholders
-Custom validators can be defined for placeholders.
+#### Defining custom URL Value Converters
 
-For example, the placeholder `<department>` should only contain the strings `['men','women','kids']`. If it doesn't contain any of these, the URL pattern should not match.
+You can define custom URL Value Converters for URL placeholders.
 
-Add the custom value converter to the `[String: URLValueConverter]` dictionary on your instance of `Navigator`.
+For example, the placeholder `<region>` is only allowed for the strings `["us-west-1", "ap-northeast-2", "eu-west-3"]`. If it doesn't contain any of these, the URL pattern should not match.
+
+Add a custom value converter to the `[String: URLValueConverter]` dictionary on your instance of `Navigator`.
 
 ```swift
-navigator.matcher.valueConverters["dept-type"] = { pathComponents, index in
-  let departments = ["men", "women", "kids"]
-  if departments.contains(pathComponents[index]) {
+navigator.matcher.valueConverters["region"] = { pathComponents, index in
+  let allowedRegions = ["us-west-1", "ap-northeast-2", "eu-west-3"]
+  if allowedRegions.contains(pathComponents[index]) {
     return pathComponents[index]
   } else {
     return nil
   }
 }
 ```
 
-You will then be able to add the validator to a placeholder in the same way that standard validators are included.
-
-For example, `myapp://user/browse/<dept-type:department>` matches with:
-- `myapp://user/browse/men`
-- `myapp://user/browse/women`
-- `myapp://user/browse/kids`
+With the code above, for example, `myapp://region/<region:_>` matches with:
+- `myapp://region/us-west-1`
+- `myapp://region/ap-northeast-2`
+- `myapp://region/eu-west-3`
 
 But it doesn't match with:
-- `myapp://user/browse/babies`
+- `myapp://region/ca-central-1`
 
-For additional information, see the [implementation](https://github.com/devxoul/URLNavigator/blob/master/Sources/URLMatcher/URLMatcher.swift) of default validators.
+For additional information, see the [implementation](https://github.com/devxoul/URLNavigator/blob/master/Sources/URLMatcher/URLMatcher.swift) of default URL Value Converters.
 
 
 ## License