How can I convert a fasta file with it's associated qual file into a fastq file?

Example:

==> contigs.fas <==
>Contig1 2221 reads, 573 bases
CAAGGAAGTGCTCCAGRAGCTGCAGGTGGGAATTCTCTTGCTTCAACAATAACGTCTCTTTCAGAAGGCATTGGTATCT
TTTCCCCACTTCCAAGCATTTTTTCAACTAATCTTATGTTATTAACCATTTCCTTAAATTCTTCTGGGTCTGCTGACAA
AGCATGATCAGGACCTTCCATATTTTTATCTAAGGTAAAGTGCTTCTCAATAACATCCGCTCCTAAGGCAACAGAAACT
ACTGGGGCGAGTATTCCCAATGTATGGTCAGAATATCCCACAGGGATATTGAATATACTTTTCAAGGTTTTAATAGCGT
TTAAATTGACATCTTCATAAGGGGTTGGGTAAGATGAAATACAATGCAATAAAATAATATCCCTGCATCCATTATTTTC
TAAAACTTTAACTGCTTCCCAAATTTCCCCAATATCAGACATTCCTGTAGATAAAATCACCGGCTTGCCTGTTTTTGCC
ACTTTTTCTAATAAGGGATAAAAGGTTAAATCACCAGAGGCAATTTTAAATCAGGCACATAAAAAAAAAAAGAAAAAAA
AAARCTCCTAGTAGACGATC
>Contig2 1005 reads, 266 bases
[...]

==> contigs.qual <==
>Contig1 2221 reads, 573 bases
49 48 42 50 42 47 37 46 45 47 43 41 39 33 43 38 33 52 53 65 46 63 55 46 59 48 
20 31 30 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 
[...]