Function create_version 

pub fn create_version(
    conn: &Connection,
    name: &str,
    branch: &str,
    parent_id: Option<i64>,
    description: Option<&str>,
) -> Result<i64>

Create a new version. Returns the version ID.

Allocates the lowest free bit_slot in [0, 63]. Returns Error::VersionLimitExceeded when all 64 slots are occupied by live versions (deleting a version frees its slot for reuse).