pgs command

# pgs - Property Graph Schemas

A property graph schema contains a list of `CREATE` node/edge/graph `TYPE` statements. It follows the grammar from the PGSchema paper with some extensions for property constraints.

The full grammar is available here.

An example property graph schema is:

    CREATE NODE TYPE ( PersonType : Person {
        name: STRING,
        OPTIONAL age: INTEGER
    }) ;
    CREATE NODE TYPE ( StudentType : Person & Student {
        name: STRING,
        OPTIONAL age: INTEGER
    }) ;
    CREATE NODE TYPE ( CourseType: Course {
        name: STRING
    })