Downgrade knex

Fix https://github.com/tgriesser/knex/issues/1701

defaultDbOptions.json

@@ -1,7 +1,6 @@
 {
   "client": "sqlite3",
   "connection": { "filename": ":memory:" },
-  "pool": { "refreshIdle": false, "min": 1, "max": 1 },
   "debug": false,
   "migrate": true
 }

package.json

@@ -46,7 +46,7 @@
     "graphql": "^0.8.0",
     "graphql-tools": "^0.8.1",
     "js-data": "^2.9.0",
-    "knex": "^0.12.6",
+    "knex": "0.11.10",
     "lodash": "^4.15.0",
     "minimist": "^1.2.0",
     "morgan": "^1.7.0",