Add ability to customize command-line arguments passed to Ruby

README.md

@@ -21,6 +21,11 @@ Your Config in Atom menu):
   # ruby path. run `which ruby` to find the path.
   'rubyExecutablePath': null
 
+  # additional arguments arguments passed to ruby.
+  # default: -c -w --external-encoding=utf-8 --internal-encoding=utf-8
+  # add -Ku if you experience problems with utf-8 encoding on macOS.
+  'rubyAdditionalArgs': '-Ku'
+
   # ignored extensions, ERB and markdown files by default.
   'ignoredExtensions': 'erb, md'
 ```

lib/main.js

@@ -14,6 +14,9 @@ export default {
       atom.config.observe('linter-ruby.rubyExecutablePath', (value) => {
         this.executablePath = value;
       }),
+      atom.config.observe('linter-ruby.rubyAdditionalArgs', (value) => {
+        this.additionalArgs = value;
+      }),
       atom.config.observe('linter-ruby.ignoredExtensions', (value) => {
         this.ignoredExtensions = value;
       }),
@@ -44,13 +47,16 @@ export default {
           return [];
         }
 
-        const execArgs = [
+        const defaultExecArgs = [
           '-c', // Check syntax only, no execution
           '-w', // Turns on warnings
           // Set the encoding to UTF-8
           '--external-encoding=utf-8',
           '--internal-encoding=utf-8',
         ];
+        const additionalArgs = this.additionalArgs.split(/\s+/);
+
+        const execArgs = defaultExecArgs.concat(additionalArgs);
         const execOpts = {
           stdin: fileText,
           stream: 'stderr',

package.json

@@ -17,6 +17,12 @@
       "type": "string",
       "default": "ruby"
     },
+    "rubyAdditionalArgs": {
+      "title": "Additional arguments passed to Ruby",
+      "description": "Default arguments: `-c -w --external-encoding=utf-8 --internal-encoding=utf-8`",
+      "type": "string",
+      "default": ""
+    },
     "ignoredExtensions": {
       "type": "array",
       "default": [