Whilst it is possible to add
. to your $PATH variable, it is highly recommended NOT to do that. If you walk around to some random place in the filesystem and type something that you think will run a program (
ps, etc), a file in the local directory will become a candidate to run. If you are unlucky, that's NOT the program you wanted to run at all - and if you are running as
root, it's even worse, because someone may well add a local file
ls that does something completely different than real
ls (along with doing real ls, of course - otherwise it would be obvious that it's not real ls, and the user would start investigating the situation). 
Instead, you should add an absolute path to where you have your executable files, e.g.
/projects/mycurrentprojects/bin - or "relative to home", e.g.
~/bin - if you want the path to work in ALL circumstances it's better to use
home\mats\bin [obviously using the right username for yourself]. That way, only files in a certan set of directories are applicable, and no matter where you are, only programs that are in those specific directories are chosen as "possible candidates to run".
 Yes, I realize that the search order and various other factors will also matter here. But it's generally not a great idea to add "current directory", no matter what objections.