feat(Ignitor): allow to set modulesRoot (#11)

Sometimes, appRoot is not necessarily the directory which contains
node_modules (for example when the AdonisJs app is in a subdirectory
of a bigger application.
`ignitor.modulesRoot(location)` allows to specify a different directory to
look for dependencies such as `@adonisjs/ace`.

src/Ignitor/index.js

@@ -47,6 +47,7 @@ class Ignitor {
   constructor (fold) {
     this._fold = fold
     this._appRoot = null
+    this._modulesRoot = null
     this._loadCommands = false
 
     /**
@@ -408,7 +409,8 @@ class Ignitor {
     this._callHooks('before', 'registerCommands')
 
     const { commands } = this._getAppAttributes()
-    const ace = require(path.join(this._appRoot, '/node_modules/@adonisjs/ace'))
+    const root = this._modulesRoot || this._appRoot
+    const ace = require(path.join(root, '/node_modules/@adonisjs/ace'))
     commands.forEach((command) => ace.addCommand(command))
 
     this._callHooks('after', 'registerCommands')
@@ -513,7 +515,8 @@ class Ignitor {
   _invokeAce () {
     this._callHooks('before', 'aceCommand')
 
-    const ace = require(path.join(this._appRoot, '/node_modules/@adonisjs/ace'))
+    const root = this._modulesRoot || this._appRoot
+    const ace = require(path.join(root, '/node_modules/@adonisjs/ace'))
     ace.wireUpWithCommander()
 
     /**
@@ -659,6 +662,22 @@ class Ignitor {
     return this
   }
 
+  /**
+   * Set application modules root. This path
+   * contains the node_modules directory with
+   * the application's dependencies.
+   *
+   * @method modulesRoot
+   *
+   * @param  {String} location
+   *
+   * @chainable
+   */
+  modulesRoot (location) {
+    this._modulesRoot = location
+    return this
+  }
+
   /**
    * Set the application file. This file exports
    * an array of providers, aceProviders, aliases

test/ignitor.spec.js

@@ -39,6 +39,12 @@ test.group('Ignitor', (group) => {
     assert.equal(ignitor._appRoot, 'foo')
   })
 
+  test('register modules root', (assert) => {
+    const ignitor = new Ignitor()
+    ignitor.modulesRoot('foo')
+    assert.equal(ignitor._modulesRoot, 'foo')
+  })
+
   test('default app file to start/app.js', (assert) => {
     const ignitor = new Ignitor()
     assert.equal(ignitor._appFile, 'start/app.js')
@@ -269,6 +275,13 @@ test.group('Ignitor', (group) => {
     }
   })
 
+  test('fire ace when app and modules roots are different', async () => {
+    const ignitor = new Ignitor(fold)
+    ignitor.appRoot(__dirname)
+    ignitor.modulesRoot(path.join(__dirname, '..'))
+    await ignitor.fireAce()
+  })
+
   test('setup resolver', async (assert) => {
     const ignitor = new Ignitor(fold)
     ignitor.appRoot(path.join(__dirname, './'))