v0.15.0

• Fix fetching a store when a relation should be converted to snake_case for the backend.
• Breaking change: the model methods toBackendAttrKey and fromBackendAttrKey are static methods now, so if you want to override this you need to do this:

from:

    toBackendAttrKey(attrKey) {
        return camelToSnake(attrKey);
    }

to:

    static toBackendAttrKey(attrKey) {
        return camelToSnake(attrKey);
    }