Using fulmatch for regex matching.

### Proposed Functionality
For regex matching, we are using re.match which only checks if the pattern/regex is present at the beginning of the string. But if that is the case then the name `pattern` sounds ambiguous cause it looks like we are defining a pattern and the input string should follow that pattern.
```
regex = '.*@domain.com'
pattern1 = 'name@domain.com' # this should match
pattern2 = 'name@domain.comSomethingElse' #This should not match
```