Update contribution instructions

doc/CONTRIBUTING.md

@@ -1,42 +1,21 @@
-## Requirements
+## Issues
+
+Always provide the following information when submitting an issue:
+- Output of `bspwm -v`.
+- Content of `bspwmrc`.
+- Steps to reproduce the problem.
+
+## Pull Requests
+
+### Requirements
 
 You must be comfortable with [C][1], [XCB][2] and [Git][3].
 
-## Coding Style
+### Coding Style
 
 I follow the [Linux Coding Style][4] with the following variations:
 - [Indent with tabs, align with spaces][5].
-- Always use braces with if/else.
-
-## Browsing the Code
-
-If you use `vim`:
-- Hitting *K* will lead you to the manual page of the function under the cursor (works with most `xcb_*` functions), sometimes you'll have to explicitly specify the section of the manual you're interested in with *3K* (e.g.: `open`).
-- Install `ctags` and run `ctags *.{c,h}` in the directory holding the source. Then, hitting *Ctrl-]* will lead you to the definition of the function/variable/structure under the cursor (to go back: *Ctrl-T*).
-- You can run `make` from `vim` with `:make` and then navigate to the next and the previous error with `:cn` and `:cp`.
-
-## Debugging
-
-To install debug executables:
-```
-make clean debug && make install
-```
-
-You can attach to a running *bspwm* process with:
-```
-gdb bspwm $(pgrep -x bspwm)
-c
-```
-
-Or if you just want to generate a backtrace (saved in `gdb.txt`):
-```
-ulimit -c unlimited
-startx
-sudo systemd-coredumpctl gdb bspwm
-set logging on
-bt full
-q
-```
+- Always use braces when using control structures.
 
 [1]: http://cm.bell-labs.com/cm/cs/cbook/
 [2]: http://www.x.org/releases/X11R7.5/doc/libxcb/tutorial/