This is a low-intensity intrastate war with foreign involvement that started after Georgia declared itself independent from the Soviet Union following a referendum on March 31 1991.

Independence turmoil

The years leading up to the declaration had seen some violent unrest in the northern region of South Ossetia between proponents of independence and Soviet Union loyalists and after the independence these tensions quickly escalated to a civil war in the fall of 1991. On September 2 the government cracked down on the opposition after a march in Tiblisi and the National Guard split into pro- and anti-government factions. The paramilitary force Mkhedrioni sided with the opposition. Forces loyal to former National Guard leader Tengiz Kitovani attacked Tiblisi and siezed government buildings on 20 December 1991 causing the president Gamsakhurdia to flee into exile on 6 February 1992.

After the successful coup, an interim government, the Military Council, was formed in Georgia. Initially it was led by a triumvirate of Jaba Ioseliani, Tengiz Sigua and Tengiz Kitovani, but it was soon chaired by Eduard Shevardnadze, the former Communist leader who returned to Tbilisi in March 1992. The 1992 elections established Shevardnadze as the Chairman of Parliament and the Head of State.
The supporters of the ousted president, the "Zviadists," responded to the coup with spontaneous street demonstrations, which were brutally suppressed by the government forces and paramilitary groups. Clashes between pro- and anti-Gamsakhurdia forces continued throughout 1992 and 1993 with Zviad Gamsakhurdia's supporters taking captive government officials and government forces retaliating with reprisal raids.

Fighting in breakaway republics (1992-93)

In 1992 fighting escalated in the two regions of South Ossetia and Abkhazia between secessionists supported by Russia and government forces. Shevardnadze agreed to a cease-fire in South Ossetia in July 1992, while fighting continued in Abkhazia where secessionist forces managed to fight back against the government and take de facto control over the territory.

Civil War (1993)

In September 1993, ousted President Zviad Gamsakhurdia took advantage of the struggle in Abkhazia to return to the city of Zugdidi and rally support from Russia against Shevardnadze's government which responded in force in October 1993 and retook the territory held by Zviadist militias. Gamsakhurdia fled and died under unclear circumstances in December 1993. Zviadist rebels melted away but continued to make occasional attacks on Government forces in the years to come.

South Ossetia

The conflicts between the central government in Tiblisi and the breakaway republics of South Ossetia and Abkhazia remained at a stalemate for some years but the election of Vladimir Putin as Russian president in 2000 and Mikheil Saakashvili coming to power in 2004 after Georgia's Rose Revolution, which ousted president Eduard Shevardnadze, had a profound impact on Georgia-Russo relations which deteriorated quickly in the coming years.

Putin started to distribute Russian passports to residents in South Ossetia and taking de facto control of South Ossetia's security institutions, including the armed forces, while Saakashvili made it a top-priority to restore South Ossetia and Abkhazia to Georgian control.

Fighting between government forces and South Ossetian militias broke out in August 2004 further escalating the tension between the parties. After diplomatic wrangling Abkhazia and South Ossetia submitted formal requests for their recognition to Russia's parliament in early March 2008. Russian president Vladimir Putin responded by authorizing official ties between the Russian government and the separatists by signing a decree.

The 2008 Russo-Georgian war

On August 1 2008 fighting broke out between government forces and South Ossetian militias which quickly escalated. On August 7, after failed diplomatic attempts, Georgian forces made a push for Tshkinvali, the regional capital of South Ossetia but were repulsed by militias and Russian troops aided by Russian air force raids. A second front was opened in Abkhazia on August 11. A cease-fire plan was signed by the warring parties on August 14-16.
Russian forces eventually withdrew to the breakaway republics on August 22. On August 26 Russian President Medvedev signed decrees recognizing the Republic of Abkhazia and the Republic of South Ossetia as sovereign independent states, which was immediately condemned by western governments.

Sources
https://en.wikipedia.org/wiki/Zviad_Gamsakhurdia#Moves_towards_independence
https://en.wikipedia.org/wiki/Georgian_Civil_War
https://en.wikipedia.org/wiki/Russo-Georgian_War