title: Fixing brew doctor warnings/errors
body: <p>I have recently installed Homebrew and RVM. However, when I tried to install a new version of Ruby into RVM:...</p>
  
  <blockquote>
    <p>rvm install 2.2</p>
  </blockquote>
  
  <p>I got the following error:</p>
  
  <pre><code>Searching for binary rubies, this might take some time.
  Found remote file https://rvm_io.global.ssl.fastly.net/binaries/osx/10.9/x86_64/ruby-2.2.0.tar.bz2
  Checking requirements for osx.
  ERROR: '/usr/local/bin' is not writable - it is required for Homebrew, try 'brew doctor' to fix it!
  Requirements installation failed with status: 1.
  </code></pre>
  
  <p>So I ran the doctor command to view errors and saw:</p>
  
  <pre><code>Please note that these warnings are just used to help the Homebrew maintainers
  with debugging if you file an issue. If everything you use Homebrew for is
  working fine: please don't worry and just ignore them. Thanks!
  
  Warning: /usr/local/bin isn't writable.
  
  This can happen if you "sudo make install" software that isn't managed by
  by Homebrew. If a formula tries to write a file to this directory, the
  install will fail during the link step.
  </code></pre>
  
  <p>I found the same issue with various other directories:</p>
  
  <pre><code>/Library/Caches/Homebrew
  /usr/local/Cellar
  /usr/local/etc
  /usr/local/include
  /usr/local/lib
  /usr/local/lib/pkgconfig
  /usr/local/opt
  /usr/local/share
  /usr/local/share/man
  /usr/local
  </code></pre>
  
  <p>When I installed RVM, I did a single user install into a non admin account. This non admin account I will be using as my development account. Is this ok, or should I be developing using an admin account? I am running into all sorts of permissions type issues; eg trying to install a gem, because of write permissions failures and am now questioning what is the proper way to develop code, without being an admin, or should I be an admin?</p>
  
  <p>I was going to start using chown to fix these errors ie</p>
  
  <blockquote>
    <p>chown $USER -R /usr/local/bin</p>
  </blockquote>
  
  <p>but, this worries me. Do I want to be changing the owner of all these system directories to my non admin account? Just want some re-assurance  really before I go ahead, it just feels, wrong. (PS; is that the correct use of chown?)</p>
  
  <p>I've seen other articles that suggest using sudo, but I've also seen artciles that say you shouldn't use sudo. Err-ing on the side of caution, I would rather not use sudo.</p>
  
  <p>Thanks.</p>