Add '--exit-code' option for 'pronto run'

With it, pronto exits with non-zero code if there were any
warnings/errors.

Resolves prontolabs#27

CHANGELOG.md

@@ -4,10 +4,12 @@
 
 ### New features
 
+* [#27](https://github.com/mmozuras/pronto/issues/27): '--exit-code' option for 'pronto run'. Pronto exits with non-zero code if there were any warnings/errors.
+
 ### Changes
 
 * [#29](https://github.com/mmozuras/pronto/issues/29): Be compatible and depend on rugged '0.21.0'.
-* Performance improvement - use Rugged::Blame instead of one provided by Grit.
-* Performance improvement - cache comments retrieved from GitHub.
+* Performance improvement: use Rugged::Blame instead of one provided by Grit.
+* Performance improvement: cache comments retrieved from GitHub.
 
 ### Bugs fixed

lib/pronto.rb

@@ -29,7 +29,9 @@ def self.run(commit = 'master', repo_path = '.', formatter = nil)
     result = run_all_runners(patches)
 
     formatter ||= default_formatter
-    formatter.format(result, repo)
+    puts formatter.format(result, repo)
+
+    result
   end
 
   def self.gem_names

lib/pronto/cli.rb

@@ -14,6 +14,10 @@ def is_thor_reserved_word?(word, type)
 
     desc 'run', 'Run Pronto'
 
+    method_option :'exit-code',
+                  type: :boolean,
+                  banner: 'Exits with non-zero code if there were any warnings/errors.'
+
     method_option :commit,
                   type: :string,
                   default: 'master',
@@ -39,7 +43,8 @@ def run
       end
 
       formatter = ::Pronto::Formatter.get(options[:formatter])
-      puts ::Pronto.run(options[:commit], '.', formatter)
+      messages = ::Pronto.run(options[:commit], '.', formatter)
+      exit(messages.count) if options[:'exit-code']
     rescue Rugged::RepositoryError
       puts '"pronto" should be run from a git repository'
     end