You can try friedel crafts acylation by reacting quinoline with c-terminal acid chloride of your peptide. Else you can form an amide bond by taking amino substituted quinoline with the c-terminal acid group of your peptide.

Synthesize Boc-protected (N-alpha) peptide acid keeping side chain protecting group intact (depending on the sequence) and perform final acylation by reacting pre-activated (preferably peptide mixed anhydride) peptide with amino quinolines and at the end remove all the protecting groups to get the quinoline derived peptide. 

If your peptide is big enough to be purified  using gel filtration or dialysis, you can do it very easy: just add big excess of 4-aminomethylquinoline (http://www.sigmaaldrich.com/catalog/product/aldrich/cds015568?lang=en®ion=US), EDC and NHS at pH 5-7, incubate couple hours and then the purification. Of course if your peptide contains D or E, you should use protected peptide.

You could also try to synthesize your peptide on a hydrazino-resin and perform the cleavage by oxidation and subsequent addition of aminoquinoline, according to: http://pubs.acs.org/doi/abs/10.1021/ol048417n.

You can try to use Solid Phase Synthesis, you can try to couple your peptide chain to a specific resin wich couples the amino group. Then you can try to couple the quinoline with different coupling agents like HOBT, DIPCDI, DIEA, HOAT and similiar. I suggest you to read some about Organic Solid Phase Synthesis, wich is a very usefull and fast method to work with peptides.

Conrad synthesis between aniline and the apt beta keto ester relatively to the substituents you want on the aromatic system, followed by esterification with the first residue of your sequence which then is coupled to your peptide c terminal (of epimerization is not a big deal for your specific scope).

• halogenation namely bromination of quinoline nucleus has been said to be possible.
• then try reaction of bromo quinoline with your peptide.