Results 4 issues of Nav B

I've a simple document with a `StringField` with a default of an empty string (`""`). When I retrieve a document, and save, it does not record it as a field...

Field-default-value

This PR enables users to add as argument to the install script the environment the scripts run in. An example of this is to run in `bash` instead of `sh`....

When I try to filter by id using `MongoengineConnectionField`, using this query: ``` {tasks(id:"5ecd4880f80bde8199d3d005") { edges { node { id state } } }}``` returns this: ```{ "data": { "tasks":...