Corruption when calling ingest more than once

[andreasnoack]

julia> for i in 1:2
         open("test$(i).txt", "w") do f
           write(f, "a\tb\n")
           write(f, "$(i)\t$(2i)\n")
         end
       end

julia> using JuliaDB

julia> ingest(["test1.txt"], "tmpcache", delim = '\t', usecache = false)
Metadata for 0 / 1 files can be loaded from cache.
Reading 1 csv files totalling 8 bytes in 1 batches...
ingDTable with 1 rows in 1 chunks:

  │ a  b
──┼─────
1 │ 1  2

julia> ingest(["test1.txt", "test2.txt"], "tmpcache", delim = '\t', usecache = false)
Metadata for 0 / 2 files can be loaded from cache.
Reading 2 csv files totalling 16 bytes in 1 batches...
DTable with 2 rows in 1 chunks:

  │ a                     b
──┼──────────────────────────
1 │ -4106979394849065894  512

if I then restart the REPL

julia> using JuliaDB

julia> ingest(joinpath.("/Users/andreasnoack/Desktop", ["test1.txt", "test2.txt"][1:2]), "tmpcache", delim = '\t', usecache = false)
Metadata for 0 / 2 files can be loaded from cache.
Reading 2 csv files totalling 16 bytes in 1 batches...
DTable with 2 rows in 1 chunks:

  │ a  b
──┼─────
1 │ 1  2
2 │ 2  4