Gradeables are complex enough to warrant their own "gradeables":
array.
For each syllabus bucket you want included, this array must have one associative
array. Each associative array has the following fields:

field:
"type":
type: string
REQUIREDThis is where the name of the bucket goes, e.g.
"lab"
or"homework"
. 
field:
"count":
type: integer
REQUIREDThe number of expected gradeables in the bucket at the end of the semester. This is used to figure out how much of a contribution each assignment has towards the total bucket’s score.

field:
"percent":
type: float
REQUIREDA number between 0.0 and 1.0 that represents the fraction of the overall semester grade that is accounted for by this particular syllabus bucket. The sum of
"percent"
fields across all buckets should add up to at least 1.0 . 
field:
"ids":
type: array of associative arraysEach entry inside this array represents one gradeable. The fields inside the associative array are:

field:
"id":
type: string
REQUIREDThe id of the gradeable. This should match the id you provided on Submitty’s Create/Edit Gradeable form.

field:
"max":
type: integer
REQUIREDThe maximum score (before extra credit) that a student can receive for this gradeable.

field:
"curve":
type: array of floatsAn optional array with 4 numbers that correspond to the minimum score required for an A, B, C, and D respectively.

field:
"percent":
type: floatAn optional number that specifies the percentage of the bucket accounted for by this gradeable. If this is omitted, Rainbow Grades will attempt to distribute the percentage points in the bucket equally among gradeables.