Update CHANGELOG.md

Author: pkuczynski

CHANGELOG.md

@@ -6,31 +6,36 @@
 
 ## 1.6.0
 
-### New features
+**New features**
 
 * `Config#fail_on_missing` option (default `false`) to raise a `KeyError` exception when accessing a non-existing key
-* Add ability to test if a value was set for a given key with `key?` and `has_key?`
+* Add ability to test if a value was set for a given key with `key?` and `has_key?` ([#182](https://github.com/railsconfig/config/pull/182))
 
 ## 1.5.1
 
-### New features
-* Add parsing of ENV variable values to Boolean type
+**New features**
+
+* Add parsing of ENV variable values to Boolean type ([#180](https://github.com/railsconfig/config/pull/180))
 
 ## 1.5.0
 
-### New features
+**New features**
+
 * Add ability to validate config schema ([#155](https://github.com/railsconfig/config/pull/155) thanks to [@ok32](https://github.com/ok32))
 * Add count to the reserved names list ([#167](https://github.com/railsconfig/config/pull/167) thanks to [@carbonin](https://github.com/carbonin))
 
-### Bug fixes
+**Bug fixes**
+
 * Correctly parse `env_prefix`, which contains `env_separator` ([#177](https://github.com/railsconfig/config/pull/177) thanks to [@rdodson41](https://github.com/rdodson41))
 
 ## 1.4.0
 
-### New features
+**New features**
+
 * Added support for passing a raw ruby hash into to both `Settings.add_source!` and `Settings.prepend_source!` ([#108](https://github.com/railsconfig/config/pull/159) thanks to [@halloffame](https://github.com/halloffame))
 
-### Bug fixes
+**Bug fixes**
+
 * Added new reserved name `test` ([#158](https://github.com/railsconfig/config/pull/158) thanks to [@milushov](https://github.com/milushov))
 * `to_hash` should not replace nested config objects with Hash ([#160](https://github.com/railsconfig/config/issues/160) thanks to [@seikichi](https://github.com/seikichi))