add alias `i` to the install command

doc/03-cli.md

@@ -65,7 +65,7 @@ php composer.phar init
   to a `composer` repository or a JSON string which similar to what the
   [repositories](04-schema.md#repositories) key accepts.
 
-## install
+## install / i
 
 The `install` command reads the `composer.json` file from the current
 directory, resolves the dependencies, and installs them into `vendor`.

src/Composer/Command/InstallCommand.php

@@ -32,6 +32,7 @@ class InstallCommand extends BaseCommand
     {
         $this
             ->setName('install')
+            ->setAliases(array('i'))
             ->setDescription('Installs the project dependencies from the composer.lock file if present, or falls back on the composer.json.')
             ->setDefinition(array(
                 new InputOption('prefer-source', null, InputOption::VALUE_NONE, 'Forces installation from package sources when possible, including VCS information.'),