Fix board family installation by providing additional_urls

Author: ianfixes

CHANGELOG.md

@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 - Improper reference to `Host` in `arduino_ci.rb` test runner is now properly qualified
+- Failure to set board manager URLs (for 3rd party board providers) has been fixed
 
 ### Security
 

REFERENCE.md

@@ -64,7 +64,7 @@ For build behavior that you'd like to persist across commits (e.g. defining the
 
 Arduino boards are typically named in the form `manufacturer:family:model`.  These definitions are not arbitrary -- they are defined in an Arduino _package_.  For all but the built-in packages, you will need a package URL.  Here is Adafruit's: https://adafruit.github.io/arduino-board-index/package_adafruit_index.json
 
-Here is how you would declare a package that includes the `potato:salad` family of boards in your `.arduino-ci.yml`:
+Here is how you would declare a package that includes the `potato:salad` set of platforms (aka "board family") in your `.arduino-ci.yml`:
 
 ```yaml
 packages:

lib/arduino_ci/arduino_backend.rb

@@ -121,7 +121,11 @@ def board_installed?(boardname)
     # @param name [String] the board name
     # @return [bool] whether the command succeeded
     def install_boards(boardfamily)
-      result = run_and_capture("core", "install", boardfamily)
+      result = if @additional_urls.empty?
+        run_and_capture("core", "install", boardfamily)
+      else
+        run_and_capture("core", "install", boardfamily, "--additional-urls", @additional_urls.join(","))
+      end
       result[:success]
     end