Bugfix: Force binary rebuild

We need to rebuild the binary whenever the plugin has changed.
Previously we were not doing this if the binary already existed. This MR
adds an override parameter to the build() function which will force a
rebuild even if the binary already exists.

The README has been updated to note that this parameter should be used
for Packer/Lazy, and when someone is troubleshooting. It won't be passed
in to the build function during the normal setup call.

Should address #55

lua/gitlab/server.lua

@@ -1,7 +1,6 @@
 -- This module contains the logic responsible for building and starting
 -- the Golang server. The Go server is responsible for making API calls
 -- to Gitlab and returning the data
-local job   = require("gitlab.job")
 local state = require("gitlab.state")
 local u     = require("gitlab.utils")
 local M     = {}
@@ -43,7 +42,7 @@ end
 
 
 -- Builds the Go binary
-M.build = function()
+M.build = function(override)
   if not u.has_delta() then
     vim.notify("Please install delta to use gitlab.nvim!", vim.log.levels.ERROR)
     return
@@ -54,8 +53,10 @@ M.build = function()
   state.settings.bin_path = parent_dir
   state.settings.bin = parent_dir .. "/bin"
 
-  local binary_exists = vim.loop.fs_stat(state.settings.bin)
-  if binary_exists ~= nil then return end
+  if not override then
+    local binary_exists = vim.loop.fs_stat(state.settings.bin)
+    if binary_exists ~= nil then return end
+  end
 
   local command = string.format("cd %s && make", state.settings.bin_path)
   local installCode = os.execute(command .. "> /dev/null")