chore: use couchdb docker in ci

bc Mini P relies on CouchDB 2 as it depends on `_bulk_get`.

Author: Johannes J. Schmidt

.travis.yml

@@ -1,6 +1,4 @@
 language: node_js
-services:
-  - couchdb
 cache:
   directories:
     - ~/.npm
@@ -9,6 +7,13 @@ notifications:
 node_js:
   - '9'
   - '8'
+services:
+  - docker
+os:
+  - linux
+before_script:
+  - docker run -d -p 5984:5984 --name couchdb couchdb
+  - while [ '200' != $(curl -s -o /dev/null -w %{http_code} http://127.0.0.1:5984) ]; do sleep 1; done
 after_success:
   - npm run travis-deploy-once "npm run semantic-release"
 branches:

README.md

@@ -40,7 +40,8 @@ pull(
 The CouchDB replication protocol replicates documents via the changes feed. This replication, though, is based on `allDocs` by now.
 
 ## Dependencies
-Mini P requires Node v8.
+Mini P requires Node v8.  
+HttpP adapter only works with CouchDB 2 (relies on `_bulk_get`).  
 The only npm dependency is `request`, which is used for the HttpP adapter.
 
 ## Example