Optimize images

## Squish Image Optimization Summary

Squish optimized 54 images for a total savings of 138 KB (32.7%).

| Image Path | Original Size | Optimized Size | Savings | Savings % |
|:--- | ---:| ---:| ---:| ---:|
| `doc/erd.png` | 141 KB | 46 KB | 95.1 KB | 67.4% |
| `public/colors.png` | 4.01 KB | 1.17 KB | 2.84 KB | 70.7% |
| `public/favicon.png` | 695 bytes | 649 bytes | 46 bytes | 6.6% |
| `public/fluid-icon.png` | 144 KB | 144 KB | 174 bytes | 0.1% |
| `public/images/arrow.png` | 356 bytes | 181 bytes | 175 bytes | 49.2% |
| `public/images/bluebox.png` | 3.09 KB | 1.75 KB | 1.34 KB | 43.4% |
| `public/images/bullet-directory.png` | 269 bytes | 183 bytes | 86 bytes | 32.0% |
| `public/images/dnsimple.png` | 3.73 KB | 2.46 KB | 1.27 KB | 34.0% |
| `public/images/edit.png` | 584 bytes | 526 bytes | 58 bytes | 9.9% |
| `public/images/downloads-icon.png` | 2.2 KB | 2.08 KB | 118 bytes | 5.2% |
| `public/images/flash.jpg` | 452 bytes | 433 bytes | 19 bytes | 4.2% |
| `public/images/flash-error.png` | 543 bytes | 458 bytes | 85 bytes | 15.7% |
| `public/images/flash-success.png` | 708 bytes | 594 bytes | 114 bytes | 16.1% |
| `public/images/gauges.png` | 3.57 KB | 2.32 KB | 1.25 KB | 35.1% |
| `public/images/go.png` | 512 bytes | 429 bytes | 83 bytes | 16.2% |
| `public/images/header.png` | 1.3 KB | 1.23 KB | 71 bytes | 5.3% |
| `public/images/letter.png` | 157 bytes | 103 bytes | 54 bytes | 34.4% |
| `public/images/leaderboard.png` | 204 bytes | 128 bytes | 76 bytes | 37.3% |
| `public/images/logo.png` | 10.8 KB | 8.39 KB | 2.38 KB | 22.1% |
| `public/images/section.png` | 202 bytes | 159 bytes | 43 bytes | 21.3% |
| `public/images/nav.png` | 9.27 KB | 5.76 KB | 3.51 KB | 37.9% |
| `public/images/pager.png` | 171 bytes | 117 bytes | 54 bytes | 31.6% |
| `public/images/paste.png` | 1.05 KB | 949 bytes | 131 bytes | 12.1% |
| `public/images/rubycentral.png` | 8.76 KB | 3.13 KB | 5.64 KB | 64.3% |
| `public/images/search.png` | 1.21 KB | 1.1 KB | 114 bytes | 9.2% |
| `public/images/sponsors/bluebox.png` | 3.02 KB | 2.12 KB | 926 bytes | 29.9% |
| `public/images/shadow.png` | 136 bytes | 89 bytes | 47 bytes | 34.6% |
| `public/images/sponsors/dnsimple.png` | 4.5 KB | 3.63 KB | 895 bytes | 19.4% |
| `public/images/subscribe.png` | 749 bytes | 683 bytes | 66 bytes | 8.8% |
| `public/images/sponsors/stillalive.png` | 3.79 KB | 1.47 KB | 2.32 KB | 61.3% |
| `public/images/sponsors/runscope.png` | 1.96 KB | 1.53 KB | 443 bytes | 22.1% |
| `public/images/sponsors/thoughtbot.png` | 2.9 KB | 1.4 KB | 1.5 KB | 51.8% |
| `public/images/thoughtbot.png` | 2.07 KB | 1.37 KB | 710 bytes | 33.6% |
| `public/images/directory.png` | 225 bytes | 115 bytes | 110 bytes | 48.9% |
| `public/images/download.png` | 694 bytes | 639 bytes | 55 bytes | 7.9% |
| `public/images/feed.png` | 691 bytes | 658 bytes | 33 bytes | 4.8% |
| `public/images/flash-notice.png` | 723 bytes | 591 bytes | 132 bytes | 18.3% |
| `public/images/gittip.png` | 1.07 KB | 342 bytes | 758 bytes | 68.9% |
| `public/images/install.png` | 208 bytes | 133 bytes | 75 bytes | 36.1% |
| `public/images/instructions.png` | 284 bytes | 163 bytes | 121 bytes | 42.6% |
| `public/images/nav-cap.png` | 523 bytes | 463 bytes | 60 bytes | 11.5% |
| `public/images/newrelic.png` | 1.75 KB | 1.31 KB | 448 bytes | 25.0% |
| `public/images/ready.png` | 457 bytes | 374 bytes | 83 bytes | 18.2% |
| `public/images/nav-sprite.png` | 19.5 KB | 14.6 KB | 4.92 KB | 25.2% |
| `public/images/set.png` | 497 bytes | 414 bytes | 83 bytes | 16.7% |
| `public/images/sponsors/gauges.png` | 4.25 KB | 2.37 KB | 1.88 KB | 44.2% |
| `public/images/sponsors/newrelic.png` | 2.56 KB | 1.34 KB | 1.22 KB | 47.5% |
| `public/images/sponsors/rubycentral.png` | 5.72 KB | 3.16 KB | 2.56 KB | 44.8% |
| `public/images/sponsors/stillalive_hover.png` | 3.83 KB | 1.47 KB | 2.36 KB | 61.6% |
| `public/images/top.png` | 1.45 KB | 1.21 KB | 244 bytes | 16.5% |
| `public/images/unsubscribe.png` | 827 bytes | 764 bytes | 63 bytes | 7.6% |
| `public/touch-icon-ipad.png` | 4.32 KB | 4.07 KB | 252 bytes | 5.7% |
| `public/touch-icon-iphone.png` | 3.45 KB | 3.26 KB | 193 bytes | 5.5% |
| `public/touch-icon-iphone4.png` | 8.04 KB | 7.53 KB | 526 bytes | 6.4% |