Don't fail if no extensions are passed to createContext options (#47)

.travis.yml

@@ -1,22 +1,22 @@
 language: node_js
 
 node_js:
-  - "6"
-  - "7"
-  - "8"
+- '6'
+- '7'
+- '8'
 
 # Use container-based Travis infrastructure.
 sudo: false
 
-env:
-  global:
-    - FANART_API_KEY=d9e25d5beda1027a1674c1585882309e
-    - THEAUDIODB_API_KEY=1
-
 branches:
   only:
   - master
-    - /^greenkeeper/.*$/
+  - "/^greenkeeper/.*$/"
+
+env:
+  global:
+  - secure: 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
+  - secure: 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
 
 script:
 - yarn test

src/context.js

@@ -17,11 +17,12 @@ export function extendContext (extension, context, options) {
   return context
 }
 
-export function createContext (options) {
+export function createContext (options = {}) {
   const { client } = options
   const loaders = createLoaders(client)
   const context = { client, loaders }
-  return options.extensions.reduce((context, extension) => {
+  const { extensions = [] } = options
+  return extensions.reduce((context, extension) => {
     return extendContext(extension, context, options)
   }, context)
 }