fix using, imports and includes

src/GroupRings.jl

@@ -1,18 +1,19 @@
-__precompile__()
 module GroupRings
 
-using AbstractAlgebra
-import AbstractAlgebra: Group, GroupElem, Ring, RingElem, parent, elem_type, parent_type, addeq!, mul!
-
 using SparseArrays
 using LinearAlgebra
 using Markdown
+using AbstractAlgebra
 
-import Base: convert, show, hash, ==, +, -, *, ^, //, /, length, getindex, setindex!, eltype, one, zero
-
-export GroupRing, GroupRingElem, complete!, create_pm, star, aug, supp
-
+import Base: ==, +, -, *, ^, //, /
+import AbstractAlgebra: Group, GroupElem, NCRing, NCRingElem, Ring
+import AbstractAlgebra: zero!, mul!, add!, addeq!, addmul!
 
+export GroupRing, GroupRingElem, aug, supp, star
 
+include("types.jl")
+include("ncring_interface.jl")
+include("arithmetic.jl")
+include("misc.jl")
 
 end # of module GroupRings