docs: add Travis and Coveralls badges

.travis.yml

@@ -9,11 +9,7 @@ cache:
     - "node_modules"
 
 branches:
-  only:
-    # This is where pull requests from "bors r+" are built.
-    - staging
-    # This is where pull requests from "bors try" are built.
-    - trying
-    # Uncomment this to enable building pull requests.
-    #- master
+  except:
+    # do not build any branches that have *.tmp in their name
+    - /.*\.tmp$/
 

README.md

@@ -1,5 +1,8 @@
 # Tree
 
+[![Build Status](https://travis-ci.org/IMA-WorldHealth/Tree.svg?branch=master)](https://travis-ci.org/IMA-WorldHealth/Tree)
+[![Coverage Status](https://coveralls.io/repos/github/IMA-WorldHealth/Tree/badge.svg?branch=master)](https://coveralls.io/github/IMA-WorldHealth/Tree?branch=master)
+
 This module provides a simple API to create trees from [adjacency lists](https://en.wikipedia.org/wiki/Adjacency_list).
 Specifically, given an array of JSON objects with ids and pointers to their parent ids, we can construct a tree
 structure and furnish operations on that structure.