Add constraints for relevant curves (#3)

ed_on_mnt4_753/src/constraints/fields.rs

@@ -0,0 +1,10 @@
+use ark_r1cs_std::fields::fp::FpVar;
+use crate::fq::Fq;
+
+/// A variable that is the R1CS equivalent of `crate::Fq`.
+pub type FqVar = FpVar<Fq>;
+
+#[test]
+fn test() {
+    ark_curve_constraint_tests::fields::field_test::<_, _, FqVar>().unwrap();
+}