This is my personal component library with boards and componenents I have used in various projects so far.
My approach is by hand, as in I write code, so I use a text-editor for this.
First I add a submodule:
$ git submodule init
$ mkdir modules
$ cd modules
$ git submodule add https://github.com/deets/kicad-lib
Then I place the following entry into the sym-lib-table
file in a project root:
(sym_lib_table
(lib (name deets)(type Legacy)(uri ${KIPRJMOD}/modules/kicad-lib/deets.lib)(options "")(descr ""))
)