updated something to prove test
added placeholder and example for image_url
added sample image
added picture URLs
updated themes on seeds
Update sample_themes.json
Merge branch 'theme-description-text' of github.com:unepwcmc/NRT into theme-description-text
Make truncate support a length argument, truncate indicator text
Show theme images
Merge pull request #159 from unepwcmc/theme-description-text

Add some proper theme descriptions, and some lovely images