fix readme (#2)

README.md

@@ -1,19 +1,19 @@
 # phos
 a self-hosted photo library
 
-# why phos?
+## why phos?
 photography's root word, phōs (φῶς), greek for "light"
 
-# why _use_ phos?
+## why _use_ phos?
 * tbd
 
-# goals
+## goals
 * improve my proficiency in gleam
 * create something I'll use every day
 * learn about design patterns
 * play with ideas
 
-# roadmap
+## roadmap
 * tbd
 
 ## contributing