Can't insert data

type User {
    username: String! @search(by: [hash, regexp]) @id
    name: String
    email: String! @search(by: [hash, regexp])
    memberships: [Membership!] @hasInverse(field: belongsTo)
    hasCredentials: [Credentials!] @hasInverse(field: forUser)
    visits: [UserVisit!]
    joinedAt: DateTime @search(by: [month])
}

type Version {
    orkId: String! @search(by: [hash]) @id
    code: String! @search(by: [regexp, hash])
    vid: String!
    gitCommit: String @search(by: [hash])
    next: Version
    previous: Version @hasInverse(field: next)
    ofBranch: Branch! @hasInverse(field: versions)
    publishedFrom: Version @hasInverse(field: publications)
    publications: [Version!]
    checkouts: [Branch!]
    artifacts: [IArtifact!] @hasInverse(field: inVersion)
    createdAt: DateTime!
    lastModified: DateTime
    createdBy: User!
    wayOfCreation: CreationType!
}

type Branch {
    orkId: String! @search(by: [hash]) @id
    changeMark: String!
    name: String! @search(by: [exact, regexp])
    versions: [Version!]!
    checkedOutFrom: Version @hasInverse(field: checkouts)
    in: Repository! @hasInverse(field: branches)
    createdAt: DateTime!
    createdBy: User!
}

enum CreationType {
    New_Version
    New_Branch
    Publish
    Root
}