title: brew doctor says "Error: /usr/bin occurs before /usr/local/bin" how to fix?
body: <pre><code>Adams-MacBook-Pro% brew doctor                                 
  
  Error: /usr/bin occurs before /usr/local/bin
  This means that system-provided programs will be used instead of those
  provided by Homebrew. The following tools exist at both paths:
  
      clusterdb
      createdb
      createlang
      createuser
      dropdb
      droplang
      dropuser
      ecpg
      git
      git-cvsserver
      git-receive-pack
      git-shell
      git-upload-archive
      git-upload-pack
      gitk
      pg_config
      pg_dump
      pg_dumpall
      pg_restore
      pg_upgrade
      psql
      reindexdb
      vacuumdb
  
  Consider amending your PATH so that /usr/local/bin
  is ahead of /usr/bin in your PATH.
  </code></pre>
  
  <p>Here is my path:</p>
  
  <pre><code>Adams-MacBook-Pro% echo $PATH                                  
  /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin
  </code></pre>
  
  <p>I thought it was dangerous to move things to the front? How do I solve this problem? Also, I'm not even sure where to find where /user/bin is declared in the path.</p>
  
  <p>Thanks</p>