add way to delete table

src/structure.jl

@@ -98,6 +98,15 @@ function Base.setindex!(db::DataBase, table::Table, name::Symbol; verbose = fals
     flush(db.schema.memory.io)
 end
 
+function Base.delete!(db::DataBase, name::Symbol)
+    # File
+    write(db.schema.memory.io, Action(delete, name), S = db.size)
+    # In memory
+    delete!(db.schema.memory.data,name)
+    # On disk
+    flush(db.schema.memory.io)
+end
+
 function Base.setindex!(tbl::DataBaseTable, object::T, index) where T
     action = haskey(tbl.memory.data, index) ? modify : create
     write(tbl.memory.io, Action(action, (index, object)))